Hi guys, I have an 06 Crew Cab Dually 4x4, it gets a lot of miles (took delivery July 5th 06, now has 46,000). It's my work truck, so it has to be reliable, but I've never been happy with the fuel mileage. Factory mpg calculator says 18mpg on the freeway at 65, my average tank is 14.5mpg, not towing a load, but I do tow quite a bit also, and when I do its 14k or more. We have a really good muffler shop that works in stainless only, they did an awesome job on my '88 Burb 4x4 gas 350. I'd like to get some improved fuel economy, more power is secondary but desirable. I'm not planning on a programmer right away, it's a maybe down the road, but if there is a major improvement to be had I'm still open to it. Should I go to the local shop and do strait pipe all the way back? 4" or 5"? Will it be so loud that it's annoying on long hauls? What about the intake side? I'm not a big fan of K&N, any recomendations? I've also heard that ditching the stock fans for electrics help.