MI5 Persecution: Buerk and Lewis deny their spying

From : fmb

Q: im new to the message board new to dodge and new to diesel. just bought a 1996 3500 dually with the cummings. i will be doing alot of towing with it 13000 to 15000 pounds. have read alot about 4 exhaust systems from the turbo back. there supposed to increase power/torque and lower egt. just wondering if anyone has any pointers on which system would be the best. what is the best muffler is 5 or 6 inch worth the extra money over 4. i would appreciate any help. thanks. .