Newbie question here. I have an 06 wrx and was reading the owners manual to find that the STi 2.5 engine and the wrx 2.5 block engine have different numbers and the compression ratios are different. It was my understanding that the blocks etc were the same. What effect does the difference in compression ratio have and what are the differences other than turbo, intercooler etc...?

dont qoute me on this but i believe that the heads on the 06 wrx and the ej257's are different.

pistons are different too.