The 230's should be fine, you might even need a 240 main. Your next mods need to be a dynojet jet kit (yea i know its like $80) because the fuel needle is alot better than stock. I wasent sure about it at first, but when I put the new needles in it cleaned up the flat spot with my pipes. Also, with that needle you never have to change your pilot jets. Then get the airbox adaptor and k&n from noss. After that you should get some aftermarket pipes depending on what terrain you ride (trails, dunes, drag). With pipes and your airfilter your banshee will be a new machine (im not kidding either). A good trick to know: say your dialing in your mains like you are, you just put in the 230's and your taking it down the road at full throttle in a high gear. Pull the choke out half way and if it runs better your main jet is lean (go up a size). If it runs worse I would leave it like it is (i like to jet mine fat just incase).