I have a 99 SP335 and was wondering if I would notice an increase in power with a power kit (ie K and N or something like it) or how to get the most bang for the buck. No upgrading to a 500,600, or a 700 is not an option.

 

the k&n filter is worth the money. this is the only thing that i have done to my 500 (other than tires). before k&n filter=57 mph. on hard ground. with k&n, an even 60mph. it does help, mabye not by much, but improvement is improvement!

 

That is about the most improvement I'd expect to get from the SP335. A slightly higher top speed. The motor really is under powered and not really anything you can do with it except what is NOT an option. A clutch kit would also help but you wouldn't really get performance, just change the performance it has.

 

I installed a K&N on my bike, power difference was ok, but is far easier to clean, especially when I already have a kit for the K&N filter in my car and truck.

 

I know I keep posting this, but it's because people keep asking and forgetting about it. Don't bother wasting your money on the K&N, or Uni-filter cleaners. You can use 409, Simple Green, or like my local Fleet Farm sells a non-flammable, biodegradable cleaner called Jungle Jake. You can get a 3 gallon parts washer for around $40, and keep this exclusively for your air filters. Multiple units on quads, and a K&N in the truck. Still use their oil though.