Roadster Roundup: Porsche Boxster S vs. Mercedes-Benz SLK55 AMG vs. BMW Z4 sDrive35is

Greg Pajo

Porsche Boxster S

BASE PRICE $61,850

Powertrain
ENGINE
24-valve DOHC flat-6
DISPLACEMENT 3.4 liters (210 cu in)
POWER 315 hp @ 6700 rpm
TORQUE 266 lb-ft @ 4500-5800 rpm
TRANSMISSION 7-speed automatic
DRIVE Rear-wheel

Chassis
STEERING
Electrically assisted
SUSPENSION, FRONT Strut-type, coil springs
SUSPENSION, REAR Multilink, coil springs
BRAKES Vented discs, ABS
TIRES Pirelli PZero
TIRE SIZE F, R 235/35YR-20, 265/35YR-20

Measurements
L x W x H
172.2 x 77.9 x 50.0 in
WHEELBASE 97.4 in
TRACK F/R 60.1/60.6 in
WEIGHT 2976 lb
WEIGHT DIST. F/R 46.0/54.0%
CARGO CAPACITY 5.3/4.6 cu ft (front trunk/rear)
EPA MILEAGE 21/30 mpg
0-60 MPH 4.5 sec
TOP SPEED 172 mph


BMW Z4 sDrive35is

BASE PRICE $65,095

Powertrain
ENGINE
24-valve DOHC twin-turbo I-6
DISPLACEMENT 3.0 liters (182 cu in)
POWER 335 hp @ 5900 rpm
TORQUE 332 lb-ft @ 1500 rpm (369 lb-ft with overboost)
TRANSMISSION 7-speed automatic
DRIVE Rear-wheel

Chassis
STEERING
Electrically assisted
SUSPENSION, FRONT Control arms, coil springs
SUSPENSION, REAR Multilink, coil springs
BRAKES Vented discs, ABS
TIRES Bridgestone Potenza RE050A
TIRE SIZE F, R 225/35YR-19, 255/30YR-19

Measurements
L x W x H
167.0 x 70.5* x 50.6 in
WHEELBASE 98.3 in
TRACK F/R 59.5/60.5 in
WEIGHT 3549 lb
WEIGHT DIST. F/R 49.3/50.7%
CARGO CAPACITY 10.9/6.4 cu ft (top up/down)
EPA MILEAGE 17/24 mpg
0-60 MPH 4.7 sec
TOP SPEED 155 mph

*width without sideview mirrors


Mercedes-Benz SLK55 AMG

BASE PRICE $68,375

Powertrain
ENGINE
32-valve DOHC V-8
DISPLACEMENT 5.5 liters (333 cu in)
POWER 415 hp @ 6800 rpm
TORQUE 398 lb-ft @ 4500 rpm
TRANSMISSION 7-speed automatic
DRIVE Rear-wheel

Chassis
STEERING
Hydraulically assisted
SUSPENSION, FRONT Strut-type, coil springs
SUSPENSION, REAR Multilink, coil springs
BRAKES F/R Vented discs/discs, ABS
TIRES Continental ContiSportContact
TIRE SIZE F, R 235/40YR-18, 255/35YR-18

Measurements
L x W x H
163.2 x 79.0 x 51.2 in
WHEELBASE 95.7 in
TRACK F/R 61.0/61.7 in
WEIGHT 3549 lb
WEIGHT DIST. F/R N/A
CARGO CAPACITY 10.1/6.4 cu ft (top up/down)
EPA MILEAGE 19/28 mpg
0-60 MPH 4.5 sec
TOP SPEED 155 mph

All measurements per manufacturers

3 of 3
JimInSF
Ok, so I've now driven both the SLK55 and Boxster, and while M-B's behavior on the DISTRONIC package is deceptive IMHO (and hopefully they will change this), the car does have some things to its credit that I don't think are adequately accounted for in the article. First off, the SLK55's chassis is great fun & fine on public roads if you're not driving at the point of traction loss on fairly grippy tires - methinks the authors are really pushing it here trying to describe this as not enough chassis for 99% of the potential customer base. In fact, it's irresponsible & misleading IMHO for them to describe driving on public roads at the limits of traction on "taxing fourth gear sweepers" - so you're expecting people to be sliding the car around at 80mph on public streets? Secondly, the Boxster's engine is ok but needs to be SCREAMED to get decent power comparatively. The AMG's V8 makes fully 50% more torque and would be much more satisfying in traffic as a DD if you don't want to drive around at 7000rpm.
mjoen
If you want to compare base prices, then the cars you test should be equipped that way. When I was comparing the Z4 to the Boxster, (before I bought the 35is), and started adding options to the Porsche, (to match what came with the 35is), I was sticker shocked. Similarly equipped, the Boxster was over $10,000 more than my Z. Porsche gouges the buyer unless they purchase a bare-bones car.Overall, this article seemed written and tweaked where necessary, to validate the authors biased opinions.
JimInSF
You mention with respect to the Boxster that "the choice of available driver-assistance systems is limited at this point" by comparison, but actually, while M-B claims to have PRE-SAFE BRAKE and various other assistance features like lane monitoring, etc. available on the SLK55 (part of the DISTRONIC PLUS package, package 997), they will refuse to actually sell you a car with those features if you try to buy one.In a bizarre bit of what feels to me like deceptive marketing, it's an official option package that they refuse to take actual orders for, it showed up in the press release for the model and is in the Dealer Ordering Guide but they have disabled the ability to actually order it in the computer and I've been told there are no plans to actually make it available. Your friendly M-B salesman will likely point out that they can sell you an SL550 with those features... bait and switch, anyone?
tinlizzy50
I used to think that roadsters were God's gift to driving enthusiasts: light, tossable, fun little toys, with manual transmissions and soft tops. Yes, ABS is good, as are no more side curtains, but heavy, hard-topped automatics?? I don't know what these cars are, but they sure don't meet my definition of "roadsters." Expensive two-seaters, yes; roadsters, no.

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