First off, a big thanks to Coal Train for your recommendations and getting me all the products quickly for the best price I saw anywhere. I have a 2006 2500 mega cab 4x4 laramie. I got it a year ago with about 70k miles. I now have 86k and have never got better than 16 mpg, avg. is 13-14mpg. I drive 100 miles to work round trip all highway at 65-70 running 1800-200 rpm. The stock fuel computer says anything between 22-26 mpg, but I never get more than 450 mi per tank.
That being said, I want to improve my fuel milage. 90% of my driving is to and from work, but I also pull a 6000lb boat up and down the Tx and La gulf coast.
So, the answer was a Smarty Jr, MBRP direct fit muffler and S&B intake. I installed all my self. The S&B air Filter is easy and about 30 min. The Smarty is simply plug-in and follow the on screen menu. Coal Train made some recommendations regarding settings. The Muffler is a bit more work ( 2hrs) and requires a sawzall or grinder. If you have an extra set of hands you could probably avoid smashing your finger and the barrage of explicative that will follow. Not too difficult, but this was my first time messing with the exhaust.
The ANSWER? Now I'm getting 550-600 miles per tank, 17+ mpg highway and perhaps slightly better around town milage than before. This is predicated on the 4 tanks of gas I have ran through her and the inconsistency of my driving. But Defiantly a large improvement. The PERFORMANCE is quite different from stock! Currently I'm running the Towing program, and the peddle response, and acceleration is awesome! you can defiantly burn up a set of tires. Pulling my boat is better also. I figure I'm able to get an extra 100 miles from a full tank or saving about 6 gal or $15 per fill up. So, with a little math I figure I would have paid for the mods with about 50-60 fill-ups depending on how much diesel costs. But the immediate performance is well worth it!