Hey Bunyip, there are lots of products like that, i have a data log but don't feel like hooking it up to the i30, but it logs data on a lot of things you just need sensors then you play it back on a lap top. but you need to know how to read it and understand . this one you are showing is simple and easy to understand but probably just a GPS.
good data log are not cheap, but mostly only needed for racing or developing.
i even know a guy with an engine dyno, that uses a controled load water wheel, that has both timed and RPM built into the software. so that you have more ways to test and use the dyno as a tool.
like say if you showed a RPM graph comparing stock i30 CRDi then a tuned virsion that got good gains at RPM, and you did a timed (with the sofware ) run you would get a more realistic idea of the result from your tune, as the timed run would show if the tune got the motor to make more power faster or slower ( this shows up throtle lag ) some tuners hate this feature as it makes a big power motor look slack as some take a long time to make that power, but if you see it on a RPM graph it will look sweet.
if martin wants to come to Sydney i can take him to learn something. i'm no expert at all but no matter how good you think you are there is always someone better.
cheers