Originally Posted by craz azn
Most of this is gathered from seeing what happens to E30s with track experience:
Front subframe: motor mount ears crack off long before the sway bar brackets break off (which can happen with monster bars). You can buy reinforcement plates from Turner, BW, etc much like it is for the E36/46.
Rear subframes are fine, unless they are rusty. Rear floor failures don't happen to E30s like they do E36/46. Worst that happens is the diff mount tab tears out, but you need an abusive driver and a ton of HP to make it happen. More commonly seen on M Roadsters and such.
Front Towers are more less the same strength as E36/46. The tops can mushroom if hit hard enough. Look around for rust near the towers... good places for it to hide. Rear towers don't have much problems, maybe if driven with broken shock mounts for a long time it may start to crack, much like E36/46.
Great info, Thanks. If I get this car it probably wont see much track use but I cant speak for the future.
So, how much power you think the diff will take or the subfloor will take? I only ask because I might swap something interesting down the road. There are 2 voices in my head, one says get a clean E30 and keep in stock , other says make it a stock looking monster.
I've got a variety of motors that can go in there if I wanted to raging from 190 to 360hp. just wanted to know if the rear end will take it before being totally reinforced and without buying a new diff.