CAMRY'S 2AR-FE is an all-aluminum, naturally-aspirated DOHC 2.5-liter. It had little to do with performance in stock form, making from 169 to 180 hp, but like other great engines made by Toyota, it was extensively overengineered to guarantee unrivaled reliability. Of course, all that overengineering means it can handle more power than it makes in factory spec. The first and most critical upgrade is a forced induction system which can include a turbo or a supercharger. This mod, plus an aftermarket exhaust system and a good ECU tune, will be enough to unlock around 300 hp. More extensive tuning, including performance cams, forged internals, a revamped fuel delivery system, and head porting, will enable the 2.5-liter to spit around 600 hp on the stock block. Best of all, a 2AR-FE is very cheap, so it's an excellent choice for a budget build.