How restrictive is our stock mufflers vs. a set from racing beat or HKS? I'm running header, presilencer to Stock Catback. It sounds very quiet and seems to pull really strong. Wondering if it's worth spending $500 for an extra 5whp or whatever they claim on their website. Or am I better off upgrading to stock turbo y-pipe and mufflers?

 

You've basically removed most of the restriction already. 5whp is probably what you'll see. It's up to you, how much is 5hp worth to you and the louder sound involved?

 

I'll give you ten bucks for one of your stock mufflers.