ok. first and foremost: one doesn't put power "into" an engine. one extracts power from an engine.
next, i think that a really good tune-up (replace ALL serviceable IGN components incl: spark plugs, wires, timing check), oil change, air filter change (do a drop-in K&N if you don't already have one), fluids change (trans lube, oil change, coolant sys flush/fill), fuel injection service (maybe just a BG 401K treatment and some 'good' gas, clean the throttle body), and valve adjustment would actually make your car feel like you got more power out of it.
next, i think that a really good tune-up (replace ALL serviceable IGN components incl: spark plugs, wires, timing check), oil change, air filter change (do a drop-in K&N if you don't already have one), fluids change (trans lube, oil change, coolant sys flush/fill), fuel injection service (maybe just a BG 401K treatment and some 'good' gas, clean the throttle body), and valve adjustment would actually make your car feel like you got more power out of it.