Now that would be a good question I know it has an hmf exhaust so I would expect it should be if anything better than stock but there is also a slight toe issue definitely an issue at high speed
I've always wanted a ds650. Some people dont like the looks of them but i think they look awesome. I had an 07 Raptor 700 some years back and it topped out at 77/78 mph according to GPS. I unplugged the "speed governor" but never got it on GPS. Seeing how quick you accerlated, a stock raptor would beat you. Not knocking on the 650 though, i still really want one. I think i read somewhere that the 2000/2001 models had a higher top speed than the rest of the other years due to them having a 15 or 16 tooth front sprocket. I would buy a newer model though for the reverse gear that was added (i think in 05).