The earlier 03 car was nice, but the build quality lacked a little and it had a few niggles. Still a great car.
The turbo was much better on fuel, build was ten-fold better but it was off the pace standard. I never modified this one.
The GP is just brutal. Very raw, no back seats and the lack of sound deadening makes the works exhaust sound rip through the cabin. Bags of torque anywhere in the rev range, and its a solid car inside.
Without trying to be biased, the GP is the best of the lot. But then, its the most expensive. It certainly feels special to drive.