If you have a CVT you are limited to 8 PSI of boost. If you have a manual you can upgrade the clutch, flywheel, turbo, pistons, etc. Small modifications can add up. Carbon fiber trunk and spoiler - reduce weight. Lightweight wheels with good tires - better traction. Strut bars, springs, coilovers, or air bags, improve handling. Don't be let down if people tell you that you can't do anything to a corolla. Remember, one of the original drift cars was an AE86 corolla