^ i am rather doubtful the geometry plane that the rear trailing arm connect at would be changed. and if so nothing near where it would be that out of spec. we are talking about a wishbone system that is buffered by rubber bushing through-out.
as for the subframe mounting blocks cracking through the floor. that's from thin metal in those hollow areas. the whole floor does not show stress cracks.
OE CSL WHEELS - OE CSL BRAKES - OE AUTOFLD MIRRORS - CSL TRUNK - CSL DIFFUSER - AA TUNE - AA PULLEYS - AS 40% SSK - BILSTEIN PSS9s
CF CSL LIP - NAVI - BMWPERF CF STRUT BAR - BMW GROUP N MNTS - GRUPPE M CF INTAKE - SUPERSPRINT - UUC BRKLINES, TRANS, RTABs - H&R SWAYS - 4.10 M-SPORT DIFF