I installed a cheapo aftermarket (Gibson knockoff) SI/DO exhaust system on my truck 3 years ago. It started to rust out pretty bad already, and I didn't want the pipes banging on the bumper so I took it all off until I could get new stuff figured out. It's not that much louder, but what really surprised me is that I went from an approx. 16.5 mpg average to around 18 mpg! IS there going to be a problem with running without a muffler or pipes though?

 

Can you still hear the Radio?

 

The radio? What radio? Well yeah, since my first mod to the truck was to yank the factory stuff and install a decent system...I can hear the radio. Actually, with the cats still in place it just has a nice pleasing rumble that can be heard in the cab.