Just as a self answer to my previous post about the "specialfx.tec" file. Its seems my Western European game version might be part of the issue. I hooked up with a mate from the other side of the Atlantic to compare the files and his North American version files though all the same size are all newer than mine... and yes... his "specialfx.tec" file fixes the curb-no-grip issue on my version... So even though not an outcome I would have desired as a permanent solution. at least my game now works on-line on any public server. Strange that. If my file were corrupted, you'd think i'd have been booted for an incorrect CRC check anyway. hmm.
Well problem fixed...
PS to Slowest.
That file came with a track I downloaded years ago. basically I have "continuous work in progress" modded GTR 2 game. which transcends HD wipes / OS reinstalls etc. for private LAN use between close mates and always one fresh untouched installed for public on-line gaming. So to be honest I can't remember what track I got it from. but I seem to recall it was some sort of rally track.
The specialfx.tec file designates different types of material surfaces and grip properties for them, etc Dirt, Grass, Road Tarmac.. Curbs (multiple types) ..
etc. It makes sense that it would have been a rally track as new surfaces such as ice, snow, mud, etc would have had to be added to allow the track to work. The only track with ice I can think of at the moment is the Dragon Ice road course. Might wanna give that a try?