I am trying to race the 111R in the S-1 event. Performance points are st at 650 and although I de-tune the car completely I am still at 653 performance points. What gives? Anyone else have this problem and found a fix?
I think a previous update sort of messed up the way PP is calculated making it impossible to tune some cars within requirements of certain events. It's frustrating since the AI is in the field with two 111's on my screen in S1 right now. In fact, the 111 in my garage is stuck at 653 where I gave up trying the same thing you have run into. Find another car. Wish I could give you good news.
Try the Ferrari 512 as a substitute (if that event allows it, I don't remember as I did it ages ago)? I know it isn't the answer you want, but that's how I got hooked on the 512 when GT5P first came out...