Ok, seriously though... Start with an aftermarket exhaust, take off the airbox lid, re-jet the carburetor, install a UNI or K&N air filter and some VF3 reeds. All of these bolt-on mods will produce noticable performance gains over stock.
You can get an extended swingarm if you want it longer, but I would invest in some better shocks and tires to improve your handling, before spending money on fancy extended A-arms and a swingarm.