I'm planning on pipes and a tuner in the near future, and at this point probably just replacing the factory air filter with a K&N. I have yet to find any good info about gains from replacing the filter as opposed to the entire box. No luck so far in the tech forum. Anyone have any experience with this?

 

I just did a K&N 3909 AC but no real noticable difference, once my Samson's and PCIII are on I expect is see my scoot running cooler and some performance increase. I will know better in a few days.
So to answer your question, your bike will breath better with a full replacement of the AC but don't expect too much difference until you do the pipes and fuel management upgrade.

Da Bone

 

If you are thinking of upgrading the air cleaner alone for now. it's just fine. The K&N3909 "kit" replaces everything behind the shiny air filter cover (except for a gasket). The stock air filter really sucks (no pun intended).

Later,in addition to the K&N 3909 kit you'll need the PCIII or similar and a set of pipes or slipons. No need to have it tuned, everything is bolt on. When you order your package, the PCIII should be programmed for your specific bike configuration. You'll be glad you did.

If you order the whole package you will get a better deal, you will save $$.

 

Wait till you get everything, don't do it half way and have to spend more later
for better things then you just bought, Atleast a stage 1 SE with a K&N repalcement
filter the paper SE stage 1 sucks. Don't buy slip ons think about getting a full set of
pipes you'll be happier in the long run. just my .02

mine with Stage1 with aceze.com cover and rinehart pipes...