Ok, through a tank and a half and it is holding steady around 16 to 17 mpg's. Now that's close to what I would normally get in the summertime, but it's been much warmer than normal here.
Bottom line is I believe there is better start up, idling, and slight power and mpg improvement. I won't say it's anything drastic but I attribute it to the engine being more efficient with the new/clean plugs, wires, and coil. The older your stuff is the better the results are going to seem due to the plugs, wires, coil not being as effecient as when they are newer.
2007 JK Unlimited Sahara, Blacked Out
3.5 inch lift sitting on 35's
Poly Performance/Synergy Suspension Ball Joints
Smittybilt Oversized Tire Carrier