I'm gonna be buying the DMH performance E-cutout pretty soon and was wondering on what size to get. I think they offer 2.5" - 4 ", BUT I was thinking I'm probably gonna have to get the one that's the same size as my pipe before the CAT. Unless I do some modifying so that I can put a bigger one on. Now here's the question, if I were to get a bigger cut-out on, I know it would sound louder, but would it cause any problems with backpressure or anything like that? And would havin a bigger one mean better performance because of better air-flow??

 

the best thing to do is to get cut out the same size as your pipe in the spot you want to weld it in. opening a cut out gives you as much free airflow as it can be, no matter if you put 3" or 4" cut out on your 3" pipe - it's gonna be the same

 

alrighty then thanx guess ill have to go measure my pipes now