Some people say the program that comes with the Powertap is fine, but I've seen what that program can do and it is very much worth it to buy WKO+. I am very happy with it and the terms used in that program are used throughout the industry, and that is because WKO+ is the gold standard. Try to keep your eyes on the road too...a little safety is important. I know I had my eyes stuck on my watts for the first month. Sometimes it is better not to look at your computer, you can surprise yourself.
__________________
"Well, folks, here's the deal: I'm the best there is, plain and simple. I mean, I wake up in the morning and I piss excellence. You know, nobody can hang with my stuff. I'm just a....just a lean, shaven, American winning machine."