Your tire size, intake and exhaust mods, elevation, riding conditions, and general use of the machine determine what you need. There are several "standard" kits available for all around use and they can be modified as needed for specific use. Just did one for an 04 600 that just sees deep mud and hard use with 28" tires, snorkeled, and piped. Had to custom cut a helix for it and modify the weights a little for the best performance. Best to call me at 651-707-6706 until I get everything up on my web site as I just became a dealer a few weeks ago and am still getting things up. I have almost everything they sell in stock and ready to ship though.
Thanks,
Ryan