I just put a 240 extended swing on mine and lowered it so it wouldnt be up in the air. ive been hearing that the spring will compress more due to the extra leverage from a passenger so that may need to be upgraded. if you dont lower it that probly wont be an issue, but your rear will be up in the air, looks funny and probly screws with the handling.
As far as brand, check out board sponsors, they got the good stuff.