I would suggest a 13 tooth sprocket 1st. The 700xx and the 450r share the same front sprocket and are interchangeable. If you stick with the 14 you'll be feathering the throttle and clutch on the more technical trails. I'm used to it now, but I still want one.
I bought (in order) so far:
Air Filter.
Paddle tires.
Programmer. (that way when I get my muffler it's not the uber chunk 'o money.