I managed one full lap offline with the old version where once I hit the cobblestone before the long straight, there was no grip at all. The car would not respond to anything, like it was on oil...
Just making a note in case that hasn't been fixed...
surface material rmbl did not work in GTRE version reason I don't know as it's one of the Simbin materials. It works fine in GTR2. You already have link to new updated version 2.1 including that cobblestone fix so why do you inform this in here, you can use PM for beta test reports, thanks.