The two biggest differences between the 06/07 and 08 engines are the black sealant and case halves. The case halves were redesigned for cheaper manufacturing (there is a thread about the exact change on AF1).
Pistons, cylinders, rings, cylinder heads, valves, springs all are the same parts numbers 06 thru 08.
The reason, IMHO, that they doubled the service interval is the factory realized they were overly conservative with the ratings. Maybe for a pure race only (pro level racing) that schedule would be accurate. There are quite a few peeps around with 10K plus KM on their bikes with zero issues (maybe a burned up starter here and there).
For reference I change my oil every 300 miles and before and after every track day. Almost 1000 miles of pure punishment (commuting, highway driving, track days, attacking local parking lots, etc.). NOT ONE SINGLE PROBLEM. Maybe my bike was built on Wednesday but it rocks.
Once you get thru any teething issues you may have these bikes are bullet proof.