I have a 2000 GS, and I just got some 05 carbs and cables off ebay. I thought with that it'd be a direct swap, but then I read something about the hose routing and petcock being different in 01+ models... What all am I going to need to do to get the new carbs installed and working?

Jetting comes after 

Since you don't seem to have the new-style ON/RES/PRI switch, all you have to do (where the fuel supply is concerned) is run the vacuum hose over to the right carb instead of the left one.

However (we tried to warn you!) you may be looking at a new throttle grip to support the push-pull throttle cable setup, and a different choke cable (maybe even a new grip on the left bar too - I'm not sure.)

Study the parts fiche diagrams for the two years and see what differences you can see.

Well, I got the throttle and choke cables with it... From the replies I got before I bought it I thought that was all I'd need... If it turns out to be more trouble than it's worth, then &^%&^ it, I'll just throw em back on ebay...