it depends on your application for your supra. if it's going to be mostly a drag or auto x car, you can run higher compression for more bottom end power when using a higher octane gas i.e 110 octane. if it's going to be a daily driver, your going to want a lower compression ratio because you will mostly be using 93 octane. the stock tt motor has 8.5:1 and the na i beleive has around 10:1. a good idea fro a daily driver turbo is to never put in any other gas than premium (92 or 93 octane). the higher the octane, the less cahnce of detonation.