Mark,
while that datacam is good, it is still very limited. For example you can only see the throttle and brake as either on or off. When throttle modulation is very important info in data log to develop a better driver and tune the car. For instance, if you have to slightly lift in the turn, the data cam might still show throttle on, but good data log can tell how many pervent do you have lifted. This can tell if the car understeer, which require you to ease off the throttle, or the driver need more cojones.
I would suggest going with David from AIM. We do carry the system if you are interested.
http://aimsports.com/products/david/index.html