I've been taking to a couple of local exhaust shops who claim they can enlarge the cat to 4". Has anyone had this done, and do you think its worth it? I live in Colorado where they apparently require diesel emmisions testing every year, so I don't want to get fined for no cat. Any info especially from Colorado people who have dealt with this is greatly appreciated. Oh, my truck is 04.5 LLY. Thanks.

max08,

Not reccomended, check the price for a new one at GM and you'll get a shock. We have off road race pipes that bolt right in and that way you can keep the stock pipe intact. Give us a call if you have any questions etc.

Mark @ DPPI