I've been told by all the parts counter guys AND a couple of Team-Green folk that you "Gets what ya Gets" when it comes to piston sizes ("A" v. "B"); However, you could go thru a couple of piston boxes at a Kawi shop and try your luck.
I haven't heard anything bad about the Wiseco's Or the Mahl's (For our friends in Euro-Land). I do know that, in both cases, you want to warm your motor up REAL GOOD(!) due to slower piston expansion with those brands (Forged). A good warm up is a good idea in stock form also, for that matter (I've made a few "Emergency Choke Activation" mistakes during -2-, yes...that's right , I said -2-! BITD races due to NOT warming up correctly...John ripped me a new one when I ran it across him AFTER the FACT!)
You might wanna ping "Rick", he's pretty knowledgeable and creative with this stuff.
I've been told by some builders that you shouldn't scuff or hone the Nikasil.
About rebuilds...look to see that the little "fingers" that stick out of the bottom of the barrel (Intake side?) aren't cracked/cracking. If they are you'll notice immediately...it's a rare thing; but, it's happened.
Clean it and re-assemble with new parts.
On a personal note: I'd get a Pro-Circuit porting and "Head" job (No pun intended...you probably are into too much e-porn if you can't stop laughin'!
)
I'd, also, get a Pro-Circuit or FMF pipe while I'm at it. Some folks around here are real big on the "V-Force". I usually just put fresh Carbon reeds in (Snappy!).
I also do a quick break in ride with ATF, yes...ATF, when I put a new clutch in...which sounds like a good thing to do with all those miles.
A well packed silencer is also in order!
Good Luck,
Manny