Vortec 6.0 questions

I hate to post these questions here but the express forum is absolutely dead. 
 
First off I owned an 05 2500 with the 6.0 in it and loved the power but hated the mpg.  It was a crewcab 4x4 with the 4:10 rearend.  Yes it got 11 mpg. always.  I am considering a 2007 3500 express with the 6.0 in it.  What knid of milege are these motors getting with the 3:73 rearrends under them?  Is the 07 motor the same as the 05???   Is this the same tranny as the 4.8 tranny in the 006 silverado??  
 
 
Thanks Tom