From my side, I have not run my bike on the dyno since doing the throttle body, no time at the moment just to busy to take time off work. The throttle body does make a difference, I have tried it with both the stage 1 cam & standard cam & there is definitely an improvement on both cams, the dyno will show by how much. These types of test cost a lot of money & don't come for free. Being a working person like you, it comes out of my pocket, luckily it's one of my hobbies but an expensive one at that.
I do not know of any high compression piston that will fit the standard XT bore. If you do not want to go bigger on the bore then you can re deck the cylinder hight & alter the squish in the head, or a CNC port job. All of these are available right now from the States by Kenny all research done on Raptors.
I can tell you the cheapest option is the big bore, big torque. Head jobs range USD$600 + but offer the biggest HP gains if you want to rev the XT constantly to get the hp out of it. Kenny is unable to give the HP & torque gains for the XT660 as he is unable to test the gains, as there are no XT660's in the States to test.
As for Freez, his research is mainly done on Raptors & he helps us out with his great knowledge of these motors. If someone will pay Freez to make a super HP XT I am sure he will do it with no problems, just need someone to pay for it.
What we know.
1/ Head work can be done by Kenny or Freez.
2/Valve work can be done by Freez or Kenny.
3/Valve springs can be done by Freez or Kenny
4/ Cam shafts can be bought from the States best off Ebay or kenny directly.
5/ Throttle bodies off Kenny or Freez.
6/ Big bore pistons off Ebay or kenny has some special ones.
Give these guys a PM for pricing, playing with mods like these cost alot of money & there are no guaranty's when modifying a motor.
When I did my XT motor I did not know for sure that the stage Hot 1 cam would fit, as no had done it before, likewise the 700 Raptor cylinder, no one had solid proof that it had been done. So we are the point of other XT riders taking the performance further then I have & until that happens we are all in the dark sort off. All the Raptor mods applied to my XT have show HP & torque gains so using the Raptor motor as a base for our mods does work.
So to round things off, we do not have a commercial supplier as yet for all the mods you want, one would need to get the mods from a few different places. All the research has been done by individuals who pay out of their own pocket, with time & money against them. I can only tell what we know. As time goes by we will see more conversions & have a better understanding of these motor to what they like & need to get them to go faster.
If someone wishes to sponsor my next mods, looking at 810cc any takers?
I have added all the HP & torque gains for the forum members that have not seen them before.
http://www.xt660.com/showthread.php?t=4509