ok here is the scenerio for you people. i am about to drop in some JDM ITR pistons and ITR rods in my GSR. this will yield me about 11:3:1 and save a little weight. now, i have been talking to jeff at importreview and he told me that JE pistons will make lot more power EVEN at the same compression. i cant see that actually happening. i am a economics major and not an engineer major so can someone explain why these or any aftermarket piston, such as endyn, will be THAT much better than stock????

 

Different designs of the head of the piston can yeild VERY different performances.
Hell, just treating the top of the piston with different coatings can change performance. (All having the same compression ratio)

 

Plus there are other factors such as the aftermarket pistons are forged and are lighter