WyldCFH
Drop a Gear and Disappear!
I'd go with the K&N under seat filter. You just put it in place of the stock filter. No retune needed, and you can take it out and clean it when needed.
I'm with @Steel. If you are not wanting or needing more HP, go with the underseat K&N, simply because you only have to buy it once and clean it during service.
If you plan to ever do upgrades, go with K&N pods or Ramair now instead of spending money twice