I like the EZ although I think there is a difference with and without the boost elbow (feels like more low end without) but the ETG's are slightly cooler with the elbow. Now I am having problems with the air filters. The $$$$ mopar filter seemed to do OK, but I recently went with a Fleet Guard (OME replacement) and I instantly pull the filter minder to about 60% and it kind of feels like the truck is running out of breath about half way into 3rd gear on a full throttle run...
I do notice the EZ makes the truck a tiny bit touchy on cold mornings, but not really that bad at all. It spools alot quicker, ALOT easier to pull out in traffic and hardly ever needs to come out of OD when pulling my Jeep (about a 6,000 load). Without the EZ I was bouncing in and out of OD on the same hills (just had to put it into tow mode and let it rev alittle more).
Gas Mileage?
If my wife is standing beside me

it increased about 1. 5 MPG's... . :-laf and that is why I got it...
but in all reality, it only increased (very slightly if at all) due to it not having to down shift so much to pull the same hills.
My EGT's will kiss 1300 on a full throttle shot and start coming back down just hair to about 1250 (around about 75-80) on a full blast 0-speed limiter.
Just for clarification: Oil, Fuel, Air filters get replaced with fleet guard brands every 5,000k so that should pretty much rule out ever running into a clogged system (other than OEM limits). Injector cleaner through it twice; and fuel lubricant every couple of tanks or so.
Would I buy it again??? Yes, i still think it is a great box and is probably one of the most reliable offered to date, had mine on since 700 miles... If I would have a suggestion for improvements, place mini-flip switches in the box instead of those tiny little jumpers since switching levels is kind of a pain without some tiny needle nose pliers.
Dave