Seeing the RS500's and M3's was and still is (to look back), great, and they're far more powerful than todays, but I think the racing is far more interesting today tbh, always bank on door-to-door, bumper-to-bumper action, the field is always pretty close together, cars are pretty evenly matched throughout.
It was best from about 1994-1998, then when lots of changes started to happen it really went downhill for a few years, then from 2005-onwards it's been back to its best again