my 35i after 1 month: comparison with SLK55 AMG
Well, it's been almost a month, and a week since break-in. It's a 35i with the 7-speed dual-clutch "automated manual" and just about everything else except the Sport Package, an option that would have put me back in manually adjusted seats. The car is replacing my SLK55 AMG which I'll have for another month, so I'm able to compare them daily.
Exterior esthetics: The SLK is a beautifully designed car, but next to the new Z4 it pales in comparison. The SLK's single side crease tries to make it look longer, and does, but the car is irremediably diminutive. The Z4, on the other hand, is properly sized and ideally proportioned. Contrary to what most reviews have said, the Z4's extra 6 inches (with respect to previous iterations) were added mostly to the rear, in order to accommodate the roof. The result is perfect balance. Gone is the ridiculous Pinocchio schnoz of earlier Z4s; gone too, that oddly haunchless stance. The hood, long but without the caricature, recalls certain classic roadsters of yesteryear (think: XKE). Fore and aft are perfectly melded by the 2 curvaceously overlapping side creases. Kudos to Juliane Blasi for this spectacular design.
Behind the wheel it's a different story. The SLK is significantly faster (0–60 mph in 4.3 vs 4.8; 12.7 @ 109 quarter mile vs 13.5 @ 106), which is what you'd expect given the 55 hp difference for basically the same weight. The SLK's steering and suspension are nothing short of miraculous, which is what you'd expect from AMG. By comparison the Z4's suspension, though good, seems too soft, and its steering a bit sloppy. I notice some oversteer in the Z4 (1 road test mentioned understeer!), and the car "tracks" a bit (it likes to follow pavement grooves), which requires frequent corrections.
The Z4's dual-clutch transmission probably shifts faster--at least, it should--but they're both so fast that I can't detect a difference. The SLK upshifts seamlessly, while its downshifts can be clunky. The Z4 lets out a little exhaust burp when shifting from 1st to 2nd and from 2nd to 3rd, but overall its trans compares quite favorably to the SLK's. And I'm starting to like the burp.
The Z4's shifter buttons are far superior. BMW did it right: each button upshifts and downshifts. Moreover, the Z4 seems to shift as quickly with the buttons or the lever as when in automated mode, unlike the SLK.
The Z4 seems sluggish in D. Move the shift lever to the left into S and suddenly you have a sports car. Now press the Dynamic Driving Control button to put it in Sport or Sport Plus mode: the throttle response and shift points get even better. I was expecting more turbo lag. There is virtually none at speed when in S, only a slight--and slightly annoying--hesitation when accelerating from a stop.
Interior: Here the Z4 wins hands down. The "extended leather" option is a big plus. (Does any other car put leather on the dash?) Then there's the 9-inch nav screen, the aluminum trim, the fat, small-diameter steering wheel, the canted control panel... Ergonomically, it's no contest. I'll mention 2 examples, among many others. (1) The Z4's Premium Package includes 2-way lumbar support, which wasn't available in the SLK55. (2) In the Z4 the driver's right elbow rests on the padded console; in the SLK your arm meets hard plastic. (What were they thinking?) "A small thing," say you? Not on road trips.
Two great cars going head to head in a very small category: seriously fast roadsters with retractable hardtops for under 100 K. A new SLK similarly optioned would have cost me around $8,000 more than the Z4. For an aging boomer such as myself who likes speed but no longer wants to track his car, who expects the whole package but can't afford an SL63 AMG, the Z4 was the right choice--for now. Maybe in a few years I'll need something with engine notes like the SLK55's (food for the soul, seriously, every single time). By then maybe BMW will have come out with an M version of the Z4. If so, and if they have the good sense to leave the retractable hardtop on it, I'll be ordering.
Last edited by Eriel; 08-27-2009 at 02:32 PM.