It's not. Even with up to 2 deg neg on the front the tires will still wear very well without chopping out the inside edge. I know it sounds crazy but the additional neg camber on the front hasn't amounted to a huge scrubbing on the inside edge as many might expect. The rears have a natural tendency to wear the inside edge anyway regardless of stock alignment or additional neg. Anything under 1.9 on the rear I've found to be fine.... and not noticeably more faster wearing than with a stock set up. A street set up of say @1.5 on the front is not noticeable on the front tires if the alignment is done right and, the car steers very straight at high speed. I've done 15000 kms and my fronts are still really good. Inside edges are fine and not noticeably out of kilter with the rest of the tire wear. The rears however seem to have lost a lot more meat overall with exception of the inside edge which is now on the wear limiter bars which is typical wear for the rear tires on a porsche. Hope this helps. Even if you max out the front at its 1.1 neg (without say rotating the top strut mounts) you will feel the additional sharpness without any undue tire wear. If you want to get say 1.5 or a bit more you can rotate the stock top strut mounts. Requires removal and punching out the 3 studs and rotate etc. There is a bit more labour involved than a regular wheel alignment though. Your dealer or P wheel alignment guy should know this trick. On a turbo, no real need to screw around fitting top tarets to get extra neg under 2 deg....but to each his own on that.