My stock system rattled too. I thought it was the bed being loose but it is the exhaust. I put the muffler delete on by mufflex. The clamp seems tight but the hanger that slips in the rubber piece is too small in diameter and length. It rattles just as much as stock though. Love the sound though....

 

I ended up going back to my muffler shop and had them weld it on. No problems since.

 

What is the inlet/outlet on the mufflex magnaflow muffler? Is it 3" in/ 2.5" out?

 

i believe 3" inlet and 2" outlet... def. not 2.5 outlet