Catalytic converters
 

What are the pros and cons that come with removing your cats. I'm not worried about inspections or getting pulled over. But if my CEL comes on, but is turned off, will the truck still run lean? I also heard that with a programmer, the CEL won't come on. Help?!?!

Removing the cats wont' really make any difference in performance, is an illegal modification which could cause issues down the road, and is pretty much pointless.

However, if you insist, the search function is your friend, There are a large number of threads addressing this "mod".

Scared to ask but what about removing the resonator, pros and cons on this part please? Magnaflow (muffler only) on my 2011 f-150 and wondering about removing this. More noise more power or more no noise less power or just more noise? Thanks