Rasp (very common I know)

Chemy

This issue had been discussed before but not in the direction (I dont think) I'm going to ask it.. I currently have the F.I 12" res system with their HFC's. I do not have any intakes on the car as I will be going FI in the next 6 months with the fast intentions kit.

As many of you know, when I let off the gas and let the car slow down on its own or coast, I hear a hissssssss that will last anywhere from about 3500 rpm down to about 2000 rpm. It is faily loud.. I want to try and keep the exhaust the way it sounds now, it has the perfect volumn for me. Would test pipes make it worse or better? should I put the stock cats back on? I dont want to lose any power if I dont have to but the hiss bothers me.. sounds like an exhaust leak but its not.

Any thoughts on this please?

Thanks in advance!

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2012 Nismo, PW #512. FI CBE SS w/12" Res, Stillen g3's, UpRev, Kenwood 9990HD, Focal speakers and tweeters, Wicked Cas corner box with JL 10" w6, 35% ceramic tint, full clear bra.