Buy a 700 that you can fix using parts from the 500!!!
I just completed a 600 twin to 600 tripple swap......... well not complete yet... I've got tons of little bugs..... electrical are hopefully the last of them I'm working out right now!!!
I know you must have every single part in the original perfect factory condition with no alterations for it to work!!!
something I didn't plan is pulling the skid and track to be able to move the motor mounts, which are different on the tripples!!!
If you run into any trouble or questions dont hesitate to shoot me a PM!!!