with twin pipes you'll burn alot more fuel, and you'll probly have to rejet alot to get the best out of it, one of my friends has a 03 prox 7 with twins, burns alot of fuel per mile. so the best bet would be to stick with a single with a can. if you properly change the jets and clutching you can have power close to the same machine with twins on them. alot less hassle and headaches. so u'll have more time to ride on it rather than time working on it.
2003 Edge-X 800
Vforce 3 reeds, Powermadd Boost bottle, updated c.d.i. slp powder pro's, 1.25 predator track, fox racing clicker rear, rydefx center and skis, 1 in handle bar riser, specialty x can. 11.5 in cobra yellow tint windshield, and a sportech yellow tint lightshield.