I don't know all of the upgrades, but I do know the 2011 ALLISON is a whole new animal from the older model. They now have a solonoid in them to adjust line pressure whereas older models used a fixed valve to regulate it. There has also been some internal changes, but I haven't seen the differences side by side yet.
1995 GMC 2500 SUBURBAN powered by 01 DURAMAX/ALLISON, 3.42 gears, 261 T-case
Trans has a mild build with ALOT of help from MIKE L. which included ALTO's for C1-C4 and a PI ML converter
DIAMONDEYE 4" exhaust with a CORSA muffler, AFE stage 1 dry filter, EFILIVE, KENNEDY single pump and pump rub kit.