First on your list should be dump the stock rear tires and, get a set w/ stiffer side walls. This will get rid of the tippy feeling some complain about! Sliding will be greatly enhanced after this.

Second i'd get a K&N Filter w/ the Proflow type mount. If you see how cheesily the stock filter is held on you will know why!

3rd i'd get a nice pipe, at least the slip on. It will wake the bike up and, remove the restriction that the stock Anchor is (you'll need to rejet).

From then on it is preferance.

 

i am in the same boat as you right now, first i have to get a raptor shopping around right now, then i think i will be leaning towards chocie number b,ct has a great package that i am thinking of getting once i get the cash that comes with, pipe header, rejet,pro flow, new air filter,and a crankcase breather, they have a dyno with all the mods put on and they are pushing close to 50 ponies,but the down fall to this is it costs around 630 dollars