250-500cc 2011 WR250 part sourcing?

I'm going to look at a 2011 WR250 after work today. I hope to make an offer on it. That being said, I know that it'll need some parts. According to the seller:

1) the top-end is original (and I'm thinking it should be replaced)
2) it needs a new chain and sprockets
3) the pipe looks to be original and is pretty dented

I've not owned a dirtbike in many moons (10+ since my Yam WR400) so I'm trying to get a handle on parts costs... I'm figuring roughly $500 for the items above. And if I can live with the pipe, I'll knock $230 off the cost.

A quick google came up with Rocky Mountain ATV / MC as a decent source. Just wondering what everyone's experiences are with ordering Husky parts online...

Oh, I should also take this opportunity to ask about this particular year/model. Are there any particular trouble-spots to look out for?

I don't personally own one but the ignition comes up fairly often as problematic, at least here
aside from that, most love them

I checked out the WR yesterday and the only issue that concerns me is the color of the coolant. It was rust colored. Not opaque or milky, but orangish-brown. The seller was not any help (he's selling it for his uncle's friend...) and so far I have not been able to reach the previous owner to see if he was using OAT coolant which would explain this color.

Based on the previous owners notes about powervalve settings, fork oil levels, obvious fresh grease on the suspension grease fittings, and other details it would actually surprise me if the coolant's odd color is from neglect, but I am the type of person who likes to know "worst-case scenarios". What parts in the cooling system might rust or corrode enough to change the coolant color from your typical green to rust color without making it look milky or discolored?

BTW, this bike also has rekluse clutch. It was the 1st one that I have ever tried and it was pretty cool... :-)

I had the opportunity to speak with the original owner (person who bought it new and did all the work on the bike) and was able to confirm that he did use an OAT type coolant which explains the different color.

I made an offer and will be picking up the bike on Saturday!