stealthmeister

I installed the Borla Cat-back exhaust system about 3 months ago and for about the first 1,500 miles, it sounded very good. My best description in words was that it was a nice smooth hum, slightly louder than stock, and I was happy with it.

Recently, I've started noticing that even at idle, it was no longer a smooth hum, but has a sand-ish gritty type of sound to it. And gets really loud at around 2000 rpms and higher. Any insights on whether this is a normal occurance, or how I can resolve this? I currently have about 74k miles on my 99 Quattro MT.

Thanks so much in advance.