I currently use a Race Air Pro and have used a Tag. The Race Air seems to be more accurate with prediction than the Tag but both work well. My boy Jr. raced for a several years and we tried using the weather station for the Jr. with limited success. The Race Air has a set up prompt for type of fuel so it would be better suited for a Jr. that's on alcohol. I personally don't think it helps much with a Jr. and that's not because of it's ability to predict performance affected by the weather. What I believe to be the problem with predicting how a Jr. will perform is due to the fact that you have a 1 cylinder, 1 barrel carb. and 1 spark plug so it will be affected more by something little than a multiple cylinder engine. I don't think changes in the weather is as much of a factor as a little belt slip or the clutch going to high gear because it spins the tires a little. I'm a Computech dealer and would be more than glad to sell you a weather station but personally I don't think one will help your Jr. program much.