It may sound like a bit of a stupid question but what are the benefits of using performance air and oil filters? Does it make that much of a difference, and is it worth getting?
If you're looking for horsepower at a certain volume while getting the bike tuned on a dyno maybe. I had the K&N air filter on my FZ6 and it was tuned with it on. I was getting 4 more horses out of the bike when it got tuned.
I had Two Brothers Racing exhaust and the K&N. My FZ6 ran really strong.
It may also be more dependent on the bike you choose. My SV1000s is supposed to give me 3 more horses with just the Two Bros. exhaust and no tuning.
It can be a controversial subject because so many people make claims on different bikes and different tread mills. Humans also tend to bend data based on friendship, popularity, political position and money!
If I was going to do fuel management with a dyno on my twin, I would say yes to a K&N. Right now I'm a paper filter guy and I use the K&N oil filter for convenience. I like the nut on the end!