I've got a K&N air filter and I want to get a slip on pipe for it. I am wondering if I need a new jet kit or if my stock jet kit will work?

 

You will definately need to re-jet. If your wondering which slip on to get or what jet settings to have, do a search in the forum and you'll find lots of info on that stuff.
l8r

 

I assume you ride at saint anthonys thats where I ride and when I first got my raptor I put A K&N filter on and a white brothers slip on and I ran awsome at saint ans even beeting fully piped and jetted raptors without jetting it actually white brothers suggests that you dont jet it with just the slip on and the dealer says the same because they say they come from factory running rich at our altitude.

 

With just a slip on and your K & N you should still run good with stock jetting although you can get more out of it with larger jets. If you want to remove your airbox lid though, you definately have to rejet.