I'm assuming you all removed the cat your self ? I pretty sure here in Arkansas the muffler shop will not do it. Or at least they would not on the (cover ur ears) 2500HD I had. So if this is done I have no need to change out turbo? After I put my programmer on I was told to go with a bigger exhaust for more power. Thanks for heater help. I've never had any work done though on my coolant system.