Hi everybody, i have turbocharged my e30 2 door 1990 with a 3.0L turbo engine, and looking to run 700hp +/-

up to date my rear X member ripped off the back end running 400hp

before i wind up the boost i wanted to know what the actual shell can hold before twisting and also how to reinforce the shell, the problem is this is a road car and i would not want a roll cage X in the position of the rear seats, as i would like to keep the rear seats.

Does anybody have any ideas?