Well, i was thinking about this at work today.. and i read a article in sports car magazine about the crossfire that sparked my imagination, the article said the car felt fast, but the gearing was a bit too tall. Taking that into consideration, the size of drive wheels has a big part to do with your transmission gear ratios, and the fact that you can't spin the huge 19s out back(which is how the crossfire pulls off such impressive skid pad numbers).. now my solution, i believe running -1 or -2 sized wheels/tires would greatly help in 0-60 sprints and 1/4 mile times.. my reasoning is the smaller diameter of 17s or 18s would shorten the gear ratios, give the crossfire the ability to spin its tire to get a better launch, as that seems to be the key to getting good 0-60 times and 1/4 mile times.. of course track testing would only validate my theory as the butt dyno might not feel a big difference(and the speedo being off).. so here's what my proposal, someone pick up two rear wheels off a slk off ebay(seen a bunch of em just search for mercedes wheels), throw the same michelin pilot sports in the same width as the stock tires but different aspect ratio(run 35s on 18s and 40s on 17s)...

goto the track and do a couple runs with the stock setup and the swap wheels to the slk wheels in the back and then take a couple more runs, if you can get off some consitent runs you should see some better times..

my thoughts might not be organized right now, so let me know if you need any clarifications..