I just had kenny brown sfc installed on my 01 ss and whenever i drive semihard to hard i hear a banging noise on the drivers side either under me or more towards the rear. otherwise if i drive normally going over bumps and turns or even when i am in nuetral and rev the engine there is NO banging noise. There is a potential contact point from my exhaust pipe and the sfc, about half an inch gap. I called the place that welded them in and they told me thats what the noise probably is and that i should get motor mounts installed. will this help or am i getting screwed over. also is there really any performance gains out of motor mounts and what exactly will they do???? please help i go to the shop at 10am monday morning

dan