i personally think UNI...it supposibly lets through more air and less dift....but on the other hand a bunch of people have K&N (i do....but i bought the whole carb set up and it came with it) and yes u will need to re-jet
twin air, they are just like uni but can be cleaned more times and have 2 different filters that keeps the bigger debris out of the smaller holes. thats just my opinion
oh yeah they are like 30 bucks as well as to where K&N are like 45
have you heard of the ready filter it comes pre oiled and used for racing, the nice part is that they only cost 10 to 15 bucks and last a long time. when it gets dirty you could clean it but why bother just get a new one.
yeah....u do need to re-jet when u switch from a stock filter...urs might have been jetted a bit high for what u had before but with any motor mod is a must