They would kill any 450 out there, they bash a 690 to the edge of its life. PS although a bit of a Despres fan I think Coma is the faster rally rider, not necessarily the best just the faster. Theoretically if you could build a 450 engine with the same power as a current 450 enduro and make it last much longer and competetive with a 690 then why hasnt it been done yet? It would be an ideal engine for enduro', rally's even motorcross, low service intervals etc. If you beef up a current 450 engine to last 10.000km you will lose power and or speed. If developed, the tuning guru's will get more power out of it and lose reliability, the vicous circle starts again.
Friends in the bivouac? shit they are focussed on racing, personal goals, one secludes himelf to focus the other has other means. Both are on top of thier game, a bit like Rossi and Jorge, and therefore bash eachother at any given moment.