You are in search of the Holy Grail of all engine builders, more power for Cheap. You'll never get significant, read measurable, power gains without doing the work. If you want to acheive real power gains you'll have to increase the displacement ( bigger bore, longer stroke) or burn more fuel mixture per cycle, either through higher compression of forced induction ( turbo or supercharger), or spin the crank more times per minute to acheive more combustion cycles per minute. The only things you can do with a stock motor are optimize all of it's current profiles, make sure it gets all the fuel and air it can use at the RIGHT time. Air intakes, headers, timing, valve adjustments etc. There are some after market devices that install inline with the maf sensor to increase fuel flow by modifing the signal to make the ecu read the air as colder and denser than it really is, therby enriching the fuel mixture for a bit more power. Some work and some don't, be careful what you buy. I tried a vareity of things before I turbocharged my motor and the most significant gains were made with a Calmini header into a 2" catless exhaust, coupled with a K+N air filter in the stock airbox. On the fuel side I run a Next Level Performance Tri Phase signal modifier at the maf sensor coupled with the larger 210cc injectors I eventually ran with the Turbo. More air and fuel in, freer flowing exhaust out= more power. It ran great this way, but nothing like it does with the turbo. Remember, Anything you do to one side, must be accompanied by something on the other side to get any increase. Good Luck.
