First off, welcome to DRN.
If you read the link in the top thread, you'll find lots of answers.
Another thing to do, is a search - the topic has been covered many times.
The 200 doesn't have quite the torque of the 220 (haven't ridden a 220, so going by hearsay), but at a guess, you'll like the torque pipe. It really is personal preference - for the terrain I ride, I should like the torque pipe, but didn't, so stuck with the PC pipe.
Radvalves - I've got one just because I could get it for cheap, but couldn't honestly tell if it made any difference. Again, it's been covered many times (trying hard not to sound rude as heck, this is your first post & first KDX)
Oh, if you notice that the bike makes a racket at idle, it's probably just the KIPS valve, solution is put a quart of oil in the gearbox & see if that helps quieten it down.
Hope that helps some & honestly, there's heaps of good info in here if you take some time to search & read. If you can't find a direct answer to any question you have, feel free to post a new thread - it's just that certain topics come up every couple of days. ;)
Michelle