KayDeeXer,
I have the same year KDX-220, but I went with the Desert Rev pipe on it rather than the woods pipe as I was thinking that I would feel a need to rip it up in the sand dunes as well :)
I've modded the airbox lid and have the same TC2 silencer as well... Isn't is amazing just what a performance pipe will do for the 220? :)
Though its a little bit more work to install it (though not by much) I also got a Boyesen Rad valve and would HIGHLY recommend it for no other reason than that it smoothed out the power curve from idle to WOT... If the motor makes more power because of the RAD valve then I'm not good enough to detect it, but what I really love is that (on my bike) instead of the power coming up predictably to a sudden "hit" the bike has the same power at WOT, but the power is far more linear as you roll on the throttle, more like a 4stroke...
not certain how the rad valve accomplishes this but, but it makes riding the bike (especially in sandy or slippery conditions) far more predictable.
I would think if you are a tight woods rider, that you would also love the the way the power comes on with the valve installed...
Its not cheap, and I think a possible alternative is to go with just the Boyesen reeds if you want give it a shot...
Good luck to you!
Feanor