I have an Apexi world sport on my car right now, it is a sweet exhaust, sounds stock at idle and a nice low non-rice rumble at WOT. The problem is its only 60mm, has a resonator and a 'NA street muffler'. Should I get say a Kteller 3 inch and have an extension made to fit my edelbrock downpipe? (This is in an EK hatch, kteller only makes catbacks for ek coupes/sedans, the apex bolts right up to the edelbrock downpipe and eliminated the cat) Am I loosing a significant amount of power from the exhaust? I get 6lbs by 3000 or so rpm, and once the boost leaks are out of it and I get it on a dyno I should make good power, but I dont want to spend the $$ for a dyno tune just to switch exhausts and have to do it again.