Stuff you can do cheapest to expensive1. K&N air intake 2. High performance ecu tune*(the prices range for these but generally it greatly effects the performance, for the better)2. High flow exhaust3. Ultra- High performance tires3. Ecu upgradeAfter these is when its expensive because you have to upgrade the actual engine parts to handle the power.4. Supercharger. (Upgrade connecting rods, and crankshaft).5. Transmission Upgrade.