I am buying an '01 CC duelly. The previous owner cut the original 3 1/2" exhaust pipe about half way back and had a muffler shop install a single 3" in and dual 2 1/2" out. How will this effect EGT,s and backpressure, power, etc.? Am I in the anger zone? I'm new to diesels, so any advice is helpful. Thanx.