I have 2 GT4's and both are still on original belts (even with a lot of testing on stony carparks). The first one which I still run was one of the first kits released.
The car is pretty solid and takes a real hammering. So far in 4 yrs I have only stripped a couple of gears and broke the front body post support. The gears were my own fault. I was adamant about getting the 15/19 pinions to mesh with the standard gears without altering the chassis holes. Just doesnt work.
I just sent you an email Randman.