The only changes that were made to the car was adding a double framerail, done by Parker Chassis and adding 4 more bars to complete the current requirements for SFI (roof diagonal, additional bars in the driver's encapulation, etc.).
Works pretty darn well for being 20 years old. Spoke to Gateway when I bought the car, (I believe he has since passed) and he stated that the car was overbuilt for its time, so he was confident that not much would be needed to certify it for current spec. He was right.