I'm after a bit more of a 'grunt' from my engine. Don't really want to go down the route of an open cone filter as will cause engine to bog intially.
Would a replacment filter element make any difference to engine noise? I'm assuming not!
Believe I have a PiperX panel filter in the standard air box at present - or at least thats what the sticker says!

2006 newage 2.0 STi PPP (obviously has prodrive box and sports cat) and I have changed the centre section for a straight through pipe.

Dont really want to void warranty either.

 

I've used K+N elements in previous cars and the induction noise is slightly louder - not sure on Imprezas though?

 

Is it grunt as in a power increase your after.... or is it grunt as in noise?

stick with the panel filter in the standard air box