Yah Id defiently get a swingarm.
Thats the purpose of it, if you dont get one, you'll have too much rake on your forks making it very difficult to ride. Id get a nice billetware swingarm, (sano, five-o, sik50s, or just order it direct from billletware.com) and it will make the bike much nicer to ride.
It will also make your shock softer, so if your shock is already to soft, id go ahead and get a stiffer spring from ishock.
Call them up, Brian, Brad, or Darren are really helpful guys. I think a spring retails for 30 bucks or so.
Good luck.