You need to install the official 1.02 patch and copy the decrypted GP4.exe over the original. Both can be found here: GP4 Patchesby E744 - Grand Prix 4
Found a 'Pirelli 2012 Rims ' folder on my hard drive, uploaded its entire content here: Pirelli 2012 - 4shared As far as I can tell it should contain everything you're looking for.by E744 - Grand Prix 4