There are three main differences that I can think of:
1. The elite does not have any open sights.
2. The elite has a much more tapered barrel, making it less muzzle heavy.
3. The elite has a forked lug which makes the barrel more free floating.
The fluted barrel Extremes (45 and 50 cal) were a special run of Extrems using left over MHC barrels but not putting them in a Master Hunter stock. I believe all of the fluted barrels will have MHC stamped on the barrel. The fluteing was in part to reduce weight and aid in cooling by increasing the surface area of the barrel. The 'C' letter was to designate that the barrel had been cyrogenically treated.