I didn't read most of this thread cuzz it seemed to break down into a discussion about using the search function.
Port the stock cylinder. Most A55 peeps I know don't run kits, cuzz a ported (or even stock unported) A55 hauls. However, a ported one will go faster. I once walked in on Jesse Cutter porting an A55 jug at Ptown that bike will apparently go 40mph stock. Of course Jesse is a wizard.
Sprockets are cheap mods- but bear in mind it will alter your acceleration or top whichever way you go about it.
As far as not so cheap mods- I'm pretty sure those Bennesar pipes will bolt onto an A55. Those pipes are fucking balls out fast, but they are also very loud.
I wouldn't kit it. It's got a restricted CDI in it.