What do you use/like for your track day fun? I'm looking at Harry's on the iPhone. I didn't think it could be all that accurate, but it would like to hear user feedback. Also, which version? Rookie? Grand Prix? Check out this R&T link: http://www.roadandtrack.com/boot/ca...lub-racing-recalibrate-your-butt-65-2-roa0913 The older Vbox and Solo seem like safe bets, and I really only need 10Hz for what I'm doing. 20-40Hz would be nice, but you pay for it. I'm leaning toward the newer Solo. 10Hz native, 20Hz interpolated.