how much of a power gain would i get for my blaster with either a k&n or another aftermarket company air filter?

 

The power gain from just adding an aftermarket air filter is really minimal unless you add a pipe and rejet at the same time. Air in, air out.
I've been running K & Ns for many years and have no problems with them. I know they're expensive, but I have an extra for each ride. When one gets too dirty, install a clean one and then clean the dirty one.
I will also say I've never used a Uni and will not say anything bad about them, just that I've always had great service from the K & N.

 

well my blaster has a full fmf system and is rejetted so would the filter work any better and would i have to do ne other work since i am putting the filter on?

 

If it were me, I would definitely assume I need to rejet if I add a K&N, even though you already re-jetted when you added the pipe. If not, you have the chance of running too lean and that mistake could be costly.

I would experiment with jets until I find one that causes stumbling at full throttle and then back down from there until it goes away. This way you know you are not running too lean but are not too rich either.

I'm sure others do it differently however but I think this is a safe way to approach it. Others I think would just add the filter and if it runs ok then do nothing. A bit risky for me.

 

Since you already have the pipe, great! Adding the K & N will help, and you'll probably need to rejet.
Do plug chops, best way to see if you're jetted properly.
Warm it up good, find an area away from staging area where you can get it tapped out in 5th or 6th. Head away from staging, turn around, tap out 6th gear and hold it WOT for at least a "10" count. Now, keeping the throttle wide-open, pull in the clutch and shut off the engine and let it coast to a stop. Don't let out the clutch or let off the throttle until you stop. Then pull the plug. Black/oily=too rich and go down one main jet size and try again. White/dry=too lean and go up one main jet size and try again. You want a light/medium brown plug. That's when it's spot on! Good luck!

 

i would rather have a uni

 

how much are the K&N airfilter prices running now? thank you

 

Anywhere from 30-40 bucks not including a $10 outerware.