If your welding the swingarm, and have never welded aluminum I would highly recommend letting the shop do it. If the temp isn't just right it could end very badly. Remember the 2007 GSXR1000 recall on the frames splitting apart. The temp was too cold and didn't actually fuse the aluminum, the weld just sat ontop, but it looked great on the outside.
To each his own, but I have welded all types of steel for more than 10 years and I would not weld my own aluminum swing arm and I have access to a aluminum welder.