Ok thanks once again, and one thing =D! Is PnG3 harder to computer than GTR2?I can't provide the exact guide, but I would assume (I never got deeply into rF1 due to lack of built-in rain) that process is similar to rFactor. Some files extensions are different, but you can do a lot by editing track, championship .gdb and per car .car files. I think the best way to learn is by looking at how mods do it. IIRC F1 1994 mod tries to do something like that, where some cars appear only on some stages of the championship. Basically what you did in rF1 should work with small differences in GTR2. I remember there was a guide for .gdb file but I could not locate it today.
Because I drove Sebring 70s version on my GTR2 HQ version and it ran from the pits to track stable 120fps,
but when I drove that exact same track on my PnG3 mod, it dipped in pits to 30-50fps and on the track where it was more plain/fields etc. it was about 70-120fps...lots of changing. Tried race with 10-15 AI there and it was impossible. Fps was 9-20fps...In GTR2 I can drive 40 ai cars and frames dip never below 100.