I have a 2003 excursion with a 7.3 and considering upgrading my exhaust. I drive the vehicle daily with a mixture of highway and terrible stop and go traffic in the washington DC/northern virginia area. I get close to 17mgp city and close to 19 highway. What if any MPG increase can I plan to get my upgrading my exhaust from the turbo back. From what I have read and here I would be better to go with a 4" over a 5" as I may loose low end torque is this correct. I do tow a small 18' boat and a 27' travel trailer ocassionally but nothing to extreme. I would like some opinions on brands and sizes. I have already upgraded my intake to a Volant cold air intake and have a Diablo sports predator tuner. I would prefer to get something that will last as I plan on keeping the vehicle for a number of years so I am leaning on a 304 stainless. I have an 88 F350 4x4 and went thru a couple of exhaust before finally getting a custom stainless exhaust in the mid 90's and have never looked back outside of hangers breaking. I looked at MBRB but they no longer make a 304 stainless. I have my eye on the ANSA Silverline 304 exhaust model FS102. I would appreciate your thoughts on other 304 exhaust that may be out there and understand what performance, quality, installation and cost things I should be aware of before possibly purchasing. Any suggestions on where to purchase the cheapest would also be helpful.

Thanks a bunch!