I too have many of these cars in my GTL game (separate install), but have noticed since there are so few servers online running multiplayer games, there are of course none with Trans-Am/pony cars available.
Might there be any future consideration to adding (more) late '60s - early '70s musclecars to altbierbude servers? Or how about classic Australian Touring Cars (maybe in GTC-65 or GTC-TC-76)?
I know, I know: there are many who might disparage musclecars as big, unwieldy boats that "won't turn," but they really are fun to drive. It would just be nice to be able to race them against other live players, on servers that are active like altbierbude's.