I'm one of the few guys who tried to make my CSM handle better, and it got me absolutely nowhere.
What he said.
I spent several years with SCCA autocross aspirations, trying to make my '89 Turbo handle somewhere near decently in sweeping style bigger radius corners. It did well enough in transistions, like slaloms, but that may have been because my hands could move the wheel so quickly? :-"
Stock classes are restricted to standard size wheels, and offset had to be within 1/4" max. For the front I found stock RX-7 wheels (same bolt pattern) and enlarged the hub hole to fit. They had a wider offset of 6mm, perfect! Stock rear steel wheels.... Stock shocks on the front, Yellow Koni on the rear, adjusted full stiff... Nasty ride that way on the street, but they were internally (off of the car only) adjustable! Front sway bar swapped for one off of a base model car. Different brake pad compounds front/rear.
205/55 on the front, 185/60 on the rear. Tire pressures mattered less than anything else, and that is not common in the sport. I really tried everything I could think of... The car did get better, but never really worked, except at certain sites which demanded narrow, transition-intensive courses. Occasional, confounding success.
At the core of the problem was, IMO, that solid beam rear axle, with welded-on spindles. No adjustment anywhere, other than a tiny amount of total thrust angle. According to the shop I took it to early in my quest, the rear had 3/8" of toe-in. No wonder it would not do much more than 0.85g before the front plowed like a farm implement. I did buy a boneyard rear axle, since modifying the old one was illegal, but never got around to putting it on, or even having it checked out. Life got in the way of the desire to be competitive, I guess.
Highest the car ever got @ the SCCA Nationals was 11th, in 1998 I think.
Sucked, from my perspective. I had won in '85 with an '83 GTS. Totally different car, with a rear suspension that actually worked, and the car behaved like it was on rails. Then, there was that 8-speed....
Pardon my nostalgic rant.