Hey Max....that's my car! Haha. I am actually driving the 91 M5 to my builder in WA right now, well not this very minute, but getting ready to deliver it tomorrow. The M5 is a beast, but not for long as that beautiful motor will be yanked shortly (entire driveline actually) and grafted into "our" CS. Yes, I know I am butcher, a murderer, whatever her fate has been sealed. All this talk about AC...I plan to yank the M5 AC and put that in the CS as well. It works so perfect. My biggest decision is group 4, or stealth street....undecided as of yet. As far as the ride height, the CS will be getting coil overs to get it low. Might have to tub it a little to get some big rubber under the back if I keep the slab side look. Will have Kodiak take your BBS wheels and add outer barrels another couple inches wider.