Im learning to drift and am setting up an E30 to be mostly track for local events and i daily it as well....Im running a turbo setup on an M20 ... BC coilovers and a few other things ... a friend from local drift events who does really well with an M52 swapped E30 ran a bolt in 4 point fox body roll cage for local events in the car he ran last year..he said the main hoop fit perfectly.. Im buying an 8 point and have checked the measurements of the main hoop and the main hoop fits really well... the rest are door bars, rear struts and the struts from inside the main hoop to the floor... all of which can be adjusted no problem... this will be enough for local drift events

I dont know if anyone else here has done something similar or if this sort of thing is looked down on ... Im a pretty good welder and think I can do a good job and the parts are $250 on amazon its a mild steel kit you buy as 2 items... the main hoop and the strut kit

take care