Rotax Engine Re-Builds

[speedy king]

For my birthday i'm trying to get my Junior Rotax engine re-built but does anyone know what is actually done (sounds rather stupid as it kinda probably sais it in the name!) but i mean do they actually tune it? strip it all down and re-assemble very finely etc? and what plus points could i find? The last engine work carried out was the O rigs replaced in April 2003 and before then i think the most recent re-build was sometime like October 2002 and it's been raced by me for one and a half seasons now and has about 14 hours on it.

What could i be looking at paying? obviously i want there to be quite a difference after the re-build as at the moment most people where i race have a more powerful engine and they're all sealed. The only plus mine has is good top end speed however is still eaten alive when ever anyone from Super One comes along!

I know of a few re-builders, Force, Supertune, Head2Head and saw Supertune have quite a good record and do alot of complicated things to the engine which i don't know the meaning of!
*Cylinder Honing Nikasil
*Precision Boring
*Cylinder Head Mechining
*Barrel/Liner Facing
*Crank Split/Re-Align

If any of what i have just written is understandable could anyone shine some light of my darkened mechanical knowledge?:confused:

Thanks!