I agree with the others: good plug and wire as the minimum.
If you wanna do some slight upgrades before you drop it into the bike, pull the head and jug off, and lap them.
Get you some 400grit wet/dry sand paper, tape/glue it to a sheet of glass, wet it and start sanding in figure 8 motions. That will make a slight (slight, as in not noticeable) compression bump but more importantly make sure the gasket mating surface is flat. If you have a dremel and some small files, you can lightly "polish" the exhaust port so that it's not as rough as it is stock. But you don't wanna sand it down too far as you risk changing the port timing and fubar'ing your engine. After that, port match your exhaust gasket to the engine and you might also open up the factory exhaust flange on the muffler a bit. And you might also ditch the factory acorn nuts on the head if you feel uneasy about them.
As for any other upgrades, wait until the engine is broken in and you're running a normal gas/oil mixture before you start cranking the power and what not.