make sure the TEX files don't change names, make sure ingame graphic settings your texture quality is set on high !!!
you have a jaguar and irvine helmets means the game doesn't find the new things so it give you the default ones. Mayby you have wrote a mistake to update like:
driver1_1.tex and you wrote diver for example
i don't use a patched gp4.exe and have no problems at all