It's supposed to increase your timing 2*+. The motor is supposably retarded from the factory to satisfy EPA. Some claim 1 mpg increase, some claim none. I have a fresh tank of fuel so I'll do my calcs and report back.

I am not very mechanically inclined, I do have all the tools, but don't necisarilly like working on my truck. I did a search for the tone ring mod, of which I found much info, however, there are NO pictures of this.
Somebody did a cam sensor mod with pictures, and posted it on alot of the tone ring mod posts, causing alot of confusion (for myself anyway). I meant to take pics, but got to involved in trying to get my truck running again.

 

How does this work with the tnt timing options

 

Just checked my fuel mileage today. It is down to 14.5 mpg after I advanced the timing. This is running around empty. Before I was averaging just over 16mpg.
Truck runs very good in the low end, its very responsive. I'm going to run it without the quad xzt tow box and see how my mpg fare.