I am looking to get an xtra air filter for my 650R I would like somthing that flows more air then stock! I have looked at Twin air, and there are two models one with a cage and one without!? what one is best? also the dealer says K&N Voids your warrentie cause they can leak!, mind you how would they know I used one. anyways I would like to hear what you guys recomend! My bike is uncorked!