1999 Porsche 911 vs. 1999 Mercedes-Benz SL-Class
iSeeCars' unbiased and data-driven comparison of the 1999 Porsche 911 and 1999 Mercedes-Benz SL-Class contrasts the two cars across a broad spectrum of vehicle specifications to determine which car is better. In addition to comparing pricing and specs, iSeeCars uses all the ratings, rankings, and insights from its comprehensive analyses of each vehicle model, including calculations of reliability, safety, depreciation, value retention, and the vehicle's projected lifetime recalls (based on analyzing over 25 billion data points). This in-depth evaluation is used to identify which vehicle represents a better overall choice for shoppers who are considering both the 1999 Porsche 911 and the 1999 Mercedes-Benz SL-Class.
In comparing the 1999 Porsche 911's and the 1999 Mercedes-Benz SL-Class's specifications and ratings, the 1999 Porsche 911 has the advantage in the areas of fuel efficiency, reliability, resale value and overall quality score. The 1999 Mercedes-Benz SL-Class has the advantage in the areas of typical lower range of pricing for used cars and base engine power. Based on this comparison of the 1999 Porsche 911's and the 1999 Mercedes-Benz SL-Class's specifications and ratings, the 1999 Porsche 911 is a better car than the 1999 Mercedes-Benz SL-Class.
Pricing: A used 1999 Porsche 911 ranges from $17,432 to $33,584 while a used 1999 Mercedes-Benz SL-Class is priced between $7,860 to $32,785.
Resale/Retained Value: Looking at the 5-year depreciation rate for both models, the 1999 Porsche 911 loses 26.3 percent of its value and the 1999 Mercedes-Benz SL-Class loses 47.4 percent of its value. This means the 1999 Porsche 911 retains 21.1 percentage points more of its value and has the advantage of higher resale value versus the 1999 Mercedes-Benz SL-Class.
Quality Rating: The iSeeCars Overall Quality rating for the Porsche 911 is 9.1 out of 10 while the Mercedes-Benz SL-Class' quality rating is 7.9 out of 10. This results in the Porsche 911 being ranked 1 out of 23 Best Luxury Convertibles and the Mercedes-Benz SL-Class being ranked 5 out of 23. Out of 38 Best Luxury Sports Cars, the Porsche 911 is ranked 3 and the Mercedes-Benz SL-Class is ranked 10.
Reliability Rating: iSeeCars’ Reliability Rating for the Porsche 911 is 8.7 out of 10. For the Mercedes-Benz SL-Class the reliability rating is 7.8 out of 10. This gives the Porsche 911 a slight advantage in reliability compared to the Mercedes-Benz SL-Class.
Engine Power and Fuel Efficiency Comparison: For engine performance, the 1999 Porsche 911’s base engine makes 296 horsepower, and the 1999 Mercedes-Benz SL-Class base engine makes 302 horsepower. The 911 is rated to deliver an average of 18 miles per gallon, with a highway range of 391 miles. The SL-Class is rated to deliver an average of 17 miles per gallon, with a highway range of 441 miles.This gives the 1999 Porsche 911 the advantage in fuel efficiency and the 1999 Mercedes-Benz SL-Class the advantage in maximum range. Both models use gasoline.
New Car Pricing
Asking Price:
-
Starting MSRP:
75225
Category Avg Starting MSRP:
(Luxury Sports Cars)
65303
Category Starting MSRP Range:
(Luxury Sports Cars)
38777 - 84745
New Car Pricing
Asking Price:
-
Starting MSRP:
81695
Category Avg Starting MSRP:
(Luxury Sports Cars)
65303
Category Starting MSRP Range:
(Luxury Sports Cars)
38777 - 84745
Used Car Pricing
Avg Used Car Price:
25740
Price Range:
17432 - 33584
Category Avg Price:
(Luxury Sports Cars)
22560
Category Avg Price Range:
(Luxury Sports Cars)
17713 - 30438
# Used Cars for Sale Nationally:
36
Avg Mileage of Used Cars for Sale:
63126
# Good or Great Deals:
7
Used Car Pricing
Avg Used Car Price:
17713
Price Range:
7860 - 32785
Category Avg Price:
(Luxury Sports Cars)
22560
Category Avg Price Range:
(Luxury Sports Cars)
17713 - 30438
# Used Cars for Sale Nationally:
17
Avg Mileage of Used Cars for Sale:
72300
# Good or Great Deals:
5
Porsche 911 Scores & Rankings
Overall Score:
9.1 / 10
Reliability:
8.7 / 10
Retained Value:
9.4 / 10
Safety:
Not available
Mercedes-Benz SL-Class Scores & Rankings
Overall Score:
7.9 / 10
Reliability:
7.8 / 10
Retained Value:
8.0 / 10
Safety:
Not available
iSeeCars Reliability Insights for 1999 Porsche 911
Remaining Life Expectancy (years):
Typical Category Remaining Life Expectancy:
N/A
Category Remaining Life Expectancy Range:
N/A
Chance of Reaching 200k Miles for a New Car:
iSeeCars Reliability Insights for 1999 Mercedes-Benz SL-Class
Remaining Life Expectancy (years):
Typical Category Remaining Life Expectancy:
N/A
Category Remaining Life Expectancy Range:
N/A
Chance of Reaching 200k Miles for a New Car:
Expected 30-year Lifetime Recalls
Expected Lifetime Recalls:
2.612019991213109
Typical Category Recalls:
(Luxury Sports Cars)
1.9
Category Range for Recalls:
(Luxury Sports Cars)
1.5 - 2.6
Expected 30-year Lifetime Recalls
Expected Lifetime Recalls:
1.4583249132330058
Typical Category Recalls:
(Luxury Sports Cars)
1.9
Category Range for Recalls:
(Luxury Sports Cars)
1.5 - 2.6
Porsche 911 Rankings
Ranking
1 out of / 23Ranking
1 out of / 23Ranking
1 out of / 23Ranking
1 out of / 4Ranking
2 out of / 38Ranking
2 out of / 8Ranking
3 out of / 38Ranking
4 out of / 38Ranking
10 out of / 38Ranking
10 out of / 12Ranking
14 out of / 23Ranking
17 out of / 21Ranking
24 out of / 38Mercedes-Benz SL-Class Rankings
Ranking
5 out of / 23Ranking
6 out of / 23Ranking
6 out of / 23Ranking
7 out of / 38Ranking
9 out of / 38Ranking
9 out of / 12Ranking
10 out of / 38Ranking
12 out of / 38Ranking
12 out of / 23Ranking
14 out of / 23Ranking
15 out of / 23Ranking
15 out of / 21Ranking
19 out of / 38Ranking
22 out of / 38Ranking
31 out of / 38Available Body Styles
Convertible, Coupe
Available Body Styles
Convertible
Available Drivetrain Options
Gasoline
Available Drivetrain Options
Gasoline
1999 Porsche 911 Trim Levels
Carrera, Carrera 4
1999 Mercedes-Benz SL-Class Trim Levels
SL 500, SL 600
Warranty Information
Warranty, Bumper-to-Bumper:
4 years / 50000 miles
Warranty, Powertrain:
4 years / 50000 miles
Warranty, Roadside Assistance:
4 years / 50000 miles
Warranty Information
Warranty, Bumper-to-Bumper:
4 years / 50000 miles
Warranty, Powertrain:
4 years / 50000 miles
Warranty, Roadside Assistance:
Safety Ratings
NHTSA Safety Rating (last 5 year average):
Not yet available
2026 NHTSA Overall Rating:
Not yet available
2026 NHTSA Front Crash Overall Rating:
Not yet available
2026 NHTSA Side Crash Overall Rating:
Not yet available
2026 NHTSA Rollover Rating:
Not yet available
IIHS Safety Rating:
Not yet available
Safety Ratings
NHTSA Safety Rating (last 5 year average):
Not yet available
2026 NHTSA Overall Rating:
Not yet available
2026 NHTSA Front Crash Overall Rating:
Not yet available
2026 NHTSA Side Crash Overall Rating:
Not yet available
2026 NHTSA Rollover Rating:
Not yet available
IIHS Safety Rating:
Not yet available
Base Drivetrain Specs
Horsepower:
296 hp @ 6800 rpm
Torque:
258 foot-lbs @ 4600 rpm
Power-to-Weight Ratio (higher is better):
0.102 hp per pound
Base Drivetrain Specs
Horsepower:
302 hp @ 5600 rpm
Torque:
339 foot-lbs @ 2700 rpm
Power-to-Weight Ratio (higher is better):
0.073 hp per pound
Engine Specifications
Engine Size:
3.4 liters
Engine Configuration:
Flat/Horizontally Opposed
Number of Cylinders:
6
Transmission:
Manual
Standard/Optional Drivetrain Type:
RWD / AWD
EPA Fuel Economy
(City/Highway/Combined MPG):
15 / 23 / 18
Range (city/hwy):
255 / 391 miles
Recommended Fuel Type:
Gasoline
Engine Specifications
Engine Size:
5 liters
Engine Configuration:
V
Number of Cylinders:
8
Transmission:
Automatic
Standard/Optional Drivetrain Type:
RWD
EPA Fuel Economy
(City/Highway/Combined MPG):
14 / 21 / 17
Range (city/hwy):
294 / 441 miles
Recommended Fuel Type:
Gasoline
Standard/Optional Features
Alloy wheels:
Standard
Keyless Entry:
Standard
Leather Upholstery:
Standard
Heated Seats
Available
Navigation System:
Available
Roof Rack:
Available
Adaptive Cruise Control:
N/A
Air Suspension:
N/A
Android Auto:
N/A
Apple CarPlay:
N/A
Automatic Parking:
N/A
Bench Seats:
N/A
Bluetooth:
N/A
Captain's seat:
N/A
Cooled/Ventilated Seats:
N/A
Front Bench Seats:
N/A
Heated Steering Wheel:
N/A
Internet Radio:
N/A
Keyless Ignition:
N/A
Massage Seats:
N/A
Paddle Shifters:
N/A
Panoramic Sunroof/Moonroof
N/A
Parking Sensors:
N/A
Power Lift Gate:
N/A
Power outlet:
N/A
Quad Seats:
N/A
Roadside assistance:
N/A
Satellite radio:
N/A
Sunroof/Moonroof:
N/A
Trailer Hitch:
N/A
Voice Recognition:
N/A
Wifi:
N/A
Wireless Smartphone Charging:
N/A
Standard/Optional Features
Alloy wheels:
Standard
Keyless Entry:
Standard
Leather Upholstery:
Standard
Heated Seats
Standard
Navigation System:
N/A
Roof Rack:
N/A
Adaptive Cruise Control:
N/A
Air Suspension:
N/A
Android Auto:
N/A
Apple CarPlay:
N/A
Automatic Parking:
N/A
Bench Seats:
N/A
Bluetooth:
N/A
Captain's seat:
N/A
Cooled/Ventilated Seats:
N/A
Front Bench Seats:
N/A
Heated Steering Wheel:
N/A
Internet Radio:
N/A
Keyless Ignition:
N/A
Massage Seats:
N/A
Paddle Shifters:
N/A
Panoramic Sunroof/Moonroof
N/A
Parking Sensors:
N/A
Power Lift Gate:
N/A
Power outlet:
N/A
Quad Seats:
N/A
Roadside assistance:
N/A
Satellite radio:
N/A
Sunroof/Moonroof:
N/A
Trailer Hitch:
N/A
Voice Recognition:
N/A
Wifi:
N/A
Wireless Smartphone Charging:
N/A
Safety Features
360-Degree Camera:
N/A
Backup camera:
N/A
Blind Spot Monitoring:
N/A
Driver Attention Monitoring:
N/A
Forward Collision Warning:
N/A
Lane Departure Warning:
N/A
Lane Keeping Assist:
N/A
Pedestrian Detection:
N/A
Rear Cross-Traffic Alert:
N/A
Rear Seat Reminder:
N/A
Safety Features
360-Degree Camera:
N/A
Backup camera:
N/A
Blind Spot Monitoring:
N/A
Driver Attention Monitoring:
N/A
Forward Collision Warning:
N/A
Lane Departure Warning:
N/A
Lane Keeping Assist:
N/A
Pedestrian Detection:
N/A
Rear Cross-Traffic Alert:
N/A
Rear Seat Reminder:
N/A
Interior Dimensions
Front Head Room:
Not yet available
Front Leg Room:
Not yet available
Front Shoulder Room:
Not yet available
Rear Head Room:
Not yet available
Rear Leg Room:
Not yet available
Rear Shoulder Room:
Not yet available
Cargo Space:
Not yet available
Overall Interior Volume:
Not yet available
Interior Dimensions
Front Head Room:
37.1 inches
Front Leg Room:
42.4 inches
Front Shoulder Room:
55.4 inches
Rear Head Room:
Not yet available
Rear Leg Room:
Not yet available
Rear Shoulder Room:
Not yet available
Cargo Space:
Not yet available
Overall Interior Volume:
Not yet available
Exterior Dimensions
Curb Weight:
2901 lbs
Width:
69.5 inches
Height:
51.4 inches
Length:
174.5 inches
Wheelbase:
92.6 inches
Ground Clearance:
4.3 inches
Exterior Dimensions
Curb Weight:
4121 lbs
Width:
71.3 inches
Height:
51.3 inches
Length:
177.1 inches
Wheelbase:
99 inches
Ground Clearance:
Not yet available
Standard Wheel/Tire Information
Wheel Size:
17.0 inches
Wheel Type:
aluminum alloy
Tire Size:
Not yet available
Standard Wheel/Tire Information
Wheel Size:
17.0 inches
Wheel Type:
aluminum alloy
Tire Size:
Not yet available
Exterior Colors
Beige
Mirage Metallic
Black
Black Metallic
Blue
Dark Blue / Ocean Blue Metallic / Violet Blue Metallic / Zenith Blue Metallic
Gray
Slate Gray Metallic / Vesuvio Metallic
Green
Forest Green Metallic / Oak Green Metallic / Wimbledon Green Metallic
Purple
Viola Metallic
Red
Arena Red Metallic / Colorado Red / Guards Red
Silver
Arctic Silver Metallic / Polar Silver Metallic
White
Glacier White
Yellow
Pastel Yellow / Speed Yellow
Brown
Not available
Exterior Colors
Beige
Not available
Black
Black
Blue
Not available
Gray
Not available
Green
Mineral Green Metallic
Purple
Dark Turquoise Metallic
Red
Magma Red
Silver
Brilliant Silver Metallic / Smoke Silver Metallic
White
Glacier White
Yellow
Not available
Brown
Firemist Metallic
Interior Colors
Beige
Savanna Beige
Black
Black
Blue
Metropol Blue
Gray
Graphite Gray / Space Gray
Green
Nephrite Green
Red
Boxster Red
Brown
Not available
Interior Colors
Beige
Not available
Black
Black
Blue
Not available
Gray
Ash
Green
Not available
Red
Not available
Brown
Java / Shell
