x2 owners a carb ?

I want to purchase a new carb for my 2004 X2. Its a stock engine, but Iam going to be doing smaller upgrades to it as well, like key, larger air filter, and few other things..
Any suggestions, on what carb, air filter, velocity stack so forth..

Would really apprecitate, a more experienced owner info than me just 2nd guessing my self.

I would recommend getting a velocity stack and filter (pm me if you wanna know from where)...then get a pipe and do porting and cvt mods(which i can walk you through doing)...i wouldnt recommend upgrading the carb because it really isnt necessary on a stock motor...but if you do want a carb i have a PBU 16.5 purge carb for sale for $90 shipped so let me know