Absolutely nothing had gone wrong with this car in the time I drove it, and I really gave it a beating.
Mind you, the brakes seemed like they were sticking a little, not sure though.
I bought this car as a run around whilst my xsi 306 was off the road, I paid 400 for it with GTI wheels and mouldings, it looked gorgeous in red. what a rocket!! wiped the floor with 1600 GTI's and used to give the 1900s a run. it had a power boost valve, K&N filters and I think a high lift cam also, when the 306 was back on the road, it was no where near as fast, and that's a 2.0 16v!! and the noise from it, sounded like a jet plane. couldnt not recommend this car more highly, for the insurance, you will not find a better/faster car.
Your 306 xsi is a 8 valve, they don't come on 16 valves.
I'm guessing that the Gti s that you raced were driven by people who cudnt be bothered to race you - knowing that there would be no contest.
XS will keep up with a 1600 Gti easily, having owned both I should know...
Won't be near a 1900 tho.