As I stated earlier...there is no free lunch. One can open up the exhaust and change the intake to mak an engine "breath better" . However if you allow the engine to take in more air, whether by cold air intake or by making a freer breathing exhaust, the engine computer will automatically enrich the fuel mixture to make the proper air/fuel ratio. With a tuner you can reprogram the computer, however a lean running engine will result in internal damage due to excessive heat. Chrysler learned this the hard way when they introduced the "lean burn system" a while back. Modern fuel injected engines are a complicated mechenism and requie a lot more to make them run stronger than to just throw parts at them.
