I am one of those that was getting fairly severe oversteer. All this relates to CMP, FWIW. I did a bunch of testing Friday. My oversteer occurred mid-corner in higher speed corners. As soon as I would try to get on throttle (at or near apex) the back end would step out. I could hold the slide and drift through the corner, but I was pretty sure that it did not produce the fastest possible lap times. I tried many variations to solve this issue. Started with disconnecting rear bar. It helped, but I still had too much mid-corner oversteer. Next I lowered the rear springs 1-2 turns and put a spare tire in the trunk. This solved the oversteer issue, but created severe push in the low speed corners.
Next few iterations were on a wettish track. Reset ride height to where it started. Removed front bar in addition to rear. It was not great. Car felt unstable. Though I do think a smaller front bar may be a good wet setup. Next I removed the spare tire ballast and changed tire pressures - 5 psi lower in rear. Car felt well balanced. I also fiddled with wheel spacers, but I couldn’t tell that it made any difference.
I ran the no rear bar, no rear ballast, back to slight rake, softer rear tire pressure setup Sat/Sun. Car felt great and I got my first ever pole position - though a few fast guys were not in attendance