This reduced the HFC rasp below the level of the 'gravel in my transmission' noise from my lightweight fly wheel.

When i was putting them in last week they kept taping against the little aluminum heat shields above the stock cat location & i thought 'that is going to be an annoying rattle'

so sure enough i had the rasp 1500-3000 rpm or so

went back under the car yesterday and pulled out those 2 shields (6 10mm nuts) and the rasp is all but gone 90% improved or so

i believe that what ever vibration/rasp the new pieces are making was resonating LOUDLY against those flimsy aluminum bits - perhaps because the stock cats are wrapped in more aluminum shielding it blocked the sound waves from the pieces i took off

if i was more artsy with photoshop i'd make a f. yaa pic with the little dude ripping off those bits

anyway it really worked for my rasp.

Hope this helps!

 

I just had the same issue last week. I just bent the aluminum heat shields up out of the way. All Gone now.
I was driving my up a wall too.

 

hmm.. interesting i have rasp too from 1.5k-3krpm ..

i'll definitely look at this weekend thx for the heads up

 

cool, and i got rid of mine eventually because of the rasp...maybe ill pick up another pair