Ok this is my second aftermarket mid pipe Im on now. I previously had a 2 cat mid pipe that was ruined because the cat was destroyed by speed bumps. I just replaced that with the current Magnaflow 4 catted mid pipe i believe. The top pre cats are fine but the two in the middle scrape big speed bumps and one cat is ruined. Its now making a rattling noise. Now my question is can i keep the two pre cats on the top and remove the middle two with piping or gut them? Would it not pass emissions with the top two? Any insight? Oh btw i have like 2 inches of clearance with the midpipe.