That price does seem a tad high but you didn't mention if (along with the sales tax and extended warranty) they also added all the other dealer prep, licensing and other whacky fees they always seem to have... WIth all that factored in then I'd say (for California at least) that was a pretty decent price otd :)
I haven't heard of a four year warranty, but I got a three year warranty on my 04 KDX for $260... Maybe it was a waste, but heck, it didn't seem like so much for 3 years... Something like the CDI unit going bad is not extremely rare, and that's not cheap to replace, and its not like they're going to say "You're Rev Pipe caused that!" :) and then there's the ongoing saga of the KDX-220 exploding pistons :)
Since the default warranty is only a few months, I went for the extended... If the warranty had been a year, I would not have gotten it, since if something was going to go dreadfully wrong, it probably would have in the first year of riding...
Good luck in your searching!
Feanor