Hi Claudio,
I found this idea in forum some time ago and I do not know who wrote it:
"Editing in GP3 2000
for gp3 2000 i recommend gp3 edit (yes) the old
> one
> the trick is to copy a old gp3 exe into the gp3
> 2000 folder and you can edit helmets tyres and a
> bunch off other things..."
Perhaps you can get it to work, I havn't tried it yet, - it sounds like a good idea as the majority of the folders have the same name in GP32k and GP3 and should be patched without problems...