I have a stock 300ex and I just put a K&N airfilter on yesterday. I am going to mod the airbox with four 1 inch round holes in the top. I am also picking up a yoshimura comp full exhaust for it tomorrow. What stage Jet Kit would I want? Does it matter what stage kit I ordered, because I wasn't asked by the dealer? Does anyone know what type of gains I should expect?
Sorry for all the questions...
Thanks all!

 

Stage 2 is for air box modifications.
You will notice the pipe more and the filter. The air box holes won't do much for you. Make sure you put in some UNI filter plugs to keep all the dirt and mud away from your knn

 

Jet kits are a waste of money.
Do the mods then go by a few larger jets. Spend about $20 on jets versus $50 on the jet kit.
My 300ex with WB Eseries pipe, K&N, and air lid removed, I went from a 122 to a 142 main jet. Drilling holes does help. If you don't go near water, then just remove the lid. That way if you know your going to be by water, you can just put it back on.

 

I doubt I go into to much water, so maybe I will go without the box lid. How do I keep dust and junk away from the K&N? Do I need a precharged filter or are there other options? Homemade?

Also, if I didn't touch the box, would I want a stage 1 kit, If I buy one? I have never done any jet work, so I thought a kit might be kind of beneficial to me.

 

Whether you buy a jet kit or a bunch of jets, you will still need to know how to jet.
For the filter, buy a outerwear. The K$N works great at filtering anyways, but the outerwear keeps the fine dust off.

My advice to you is, find a friend that knows how to jet and have him help you.

 

I knew I would have to know something about jetting or know someone who knew something, but I thought there may my direction with a kit as compared to just buying the jets. I have a buddy that used to race and said he could help me if I wanted. I guess I will have to take him up on it. I bet a 6 pack will get him over to work on it.