Bought an 89 supra turbo. Racing?

[chtulu]

I bought this car to work on and to ultimately start racing on the local tracks. Anyone here a car enthusiast or racer? Anyone know what the brackets are for racing and what my car would fall under? What would I be competing against? Does it go by liters, horsepower, or anything like that? Or by year/makes/models?

Also, from what I'm reading, replacing the turbo with a twin (small/large) seems to be the way to go for high end, but I might just replace it with a larger turbo for a cheaper increase in power. Also, it seems that replacing the exhaust system is also a priority in regards to anything with a turbo. Other than these two, does anyone have advice on what would be slightly cheaper performance boosting upgrades? (the exhaust and turbo mods would be a few grand, so i'd like someone cheaper to throw on top for a slight increase).

I already have the cold air intake, and will be throwing in a stage 1 clutch (maybe centerforce?)