Ok let me be more specific. I've swapped a 4.3L M113 V8 into my SLK230. the stock 230 driveshaft puts the engine too far back in the engine bay and there is no room for the throttle body tube or exhaust. now when I put the 6 speed manual from a crossfire in it (with accompanying driveshaft), it puts the engine where it should be. (basing this on comparing to pictures)

But now I am putting an AMG 5.5L in it, and going back to Auto, but I need to know if the Crossfire has a longer (automatic) driveshaft than the SLK230. my guess is it's about 2" longer but need to be sure before buying one.