I have a WR, and found that on my first kit (Moto Trax) I had the same issue. Changed one tooth on the drive sprocket for better results. (Came stock with a 14 tooth.) Switched to a Camso this season and the overall ratio on that kit works with my bike using the stock gearing. I use third almost all day now instead of jumping back to second as I had on the previous kit. On the bright side, with the wide ratio tranny, I still get decent trail speed in 5th. Honestly wouldn't want to go any faster until they invent a ski that isn't as sketchy as what we have now...
Again, there are better bikes out there, but I had the WR and enjoy having one bike for year-round use.