I ran the tongs (gt spec) which had a 55mm Compresser side and bigger waste gate penny but I swear they did a slightly bigger one using a ct12. Good little turbos but they spool there guts out and generate a lot of heat. If you like instant boost then the only way to tell if you like it is try a hybrid. I had a speed vision gen 3 hybrid to and there very similar to the tongs gt spec but I would say the tongs is better made as the speed vision shat it's self very quickly. Each to there own, depends what you want to use the car for really. Just my opinion.