The computer is a great purchase for your bike if you don't have one. Easy to install, just follow the instructions.... I came up with 2146 over and over again like gooby. Later.
The no# that you get depends on the size and condition of your front tire. An older front tire won't measure like a new one will, and all tires are not exactly the same size. Enjoy.
What are you using the Panoram for? If it's for Enduro, then you should check out the ICO CheckMate. I know its a lot more money but it has some features found nowhere else.
I only trail and play-ride, but it's great for keeping track of distances and speed, as some of the trails we ride have speed limits enforced by sheriffs with radar on quads. :(