Which has better performance? Is the difference significant?

More important than anything:
Which one is more quiet?
(I have 16" magnaflow resonator in my b-pipe to help already, but HKS is still loud)

 

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I bought the longest Magnaflow I could fit and it was very quiet, very low key looking also. Probably substantially cheaper than the HKS too.

 

what was the longest one you found? 14" or 18"? I'm looking into 2.5" inlet/outlet

Thanks for the response. relative to stock muffler and hks hi-power, how quiet is it? I know it's hard to describe.

 

I never had a stock muffler on my car, but it was very quiet. I would definitely assume that you're going to hear your engine/intake more so than the exhaust.

Mine was 2.5 also, It was definitely closer to 18.

 

2.5" magnaflow muffler, 22" magnaflow resonator, carsound cat... on my turbo integra it is louder than stock but quieter(or about the same) noise level as the engine compartment noise. The muffler is straight-through design with steel wool? packing. It should perform like any other straight-through muffler, not sure about the noise level though.

 

thanks for the responses guys.
I need more say about the noise level if anyone had more experience, I know a lot of people here run magnaflow oval