i have an lx and its got some ***** not much but enough. i just put a aem cold air on it and there's some difference in horsepower but as for the SI it will out perform any non SI 8th gen. but needless to say the fg's have some *****, then again its all in what you want.

 

One big thing is si needs premium fuel. Ex doesnt

 

Thanks for the responses! Hard to pass up the the performance of the Si. Could someone explain the issue with 3rd gear? Thanks.

 

What would happen if you used regular gas instead of premium in the Si? Not that I would ever do that!

 

Detenation.

High compression engines need 91+ octane, or else the motor will start to ping and detenation will occur.. Which isn't good lol.