hey i have a 3.4L monte and i have flowmaster mufflers i didnt have a resonator it was rattling so had it removed. i want to replace my exaust with new pipes but still keep my mufflers i want to put a new resonator cause it pops badly. i have a real nice car keep it clean and running sweet i dont race or flaunt speed cause a 3.4L really dont have all that it sounds really good except when im parked and i rev up thats when it pops so will the resonator stop that cause i dont remember it doing that when i had one! also what will a down pipe help with i want to know cause im redoing the exhaust! Thanks!

 

here is a dyno from a 3800. basically it will give you a little more hp (i question the 15hp gains, but it is what it is i guess).

 

That is on a top swapped (via the ZZP SSM90 kit) boosted engine- so I'm betting it killed some KR too, allowing for more timing and such. I doubt you'd get those kind of gains on an NA vehicle.

A downpipe is one of the most restrictive parts of your exhaust (particularly in the ubend area)- the catback is by far the least restrictive part.