I would go with a -2 swinger. I would say a -1 if you rode hills also, wouldn't want too much traction. from my understanding with the -2 you will get more traction but it is controlable, someone with a -2 swingarm can chime in.
tOj, a member of the forums, built his banshee from the ground up, you can talk to him for some insight...but I would sugest you just buy a cheap used one...thats the best route.
is it a big improvement from socom 2? I always played socom 2...and I bought socom 1 for 10 bucks to see what it was like, and their wasnt a big changes except for a few fixes.
did you install the idle screws and new carb tops? you also have to disconnect the tors from 3 other places...their is a control box above the engine on either the left or right framel...