Hey Mike, Sounds like your makeing a valiant try at it. The mistake I know I have made is believeing everybodys advertisments and figureing if I add them up I should get about 100mpg. The other mistake was changeing to many things at once. I'm a little excessive compulsive they say. I know that what works well on one engine might not work so good on another. Point, I changed the exhaust on a gas truck a few years ago. I thought it would be awesome. Not so, I almost lost half the fuel mileage. Problem, the cam timeing was wrong for a 0 backpreassure system. I would like to see a realworld test between the 4" and 5" exhaust. I like the idea of insulateing the intake more. If I can handle the power loss, I'm running this week with the ecm backed down to stock, I will evaluate each device. There isn't much that I havn't touched so backing up might take awhile.