Since I have my new car (Audi TT RS 2010) I'm testing the new version v15 (15.0.1). I'm using Laptimer Pro on an iPhone 4s with the internal GPS within the iPhone. The OBD hardware is a PLX KiWi.
Compared to v14 on the RS4, here is my feedback:
- the RPM layout is now looking good

- the gear calculation is a bit crazy at low revs (<= 1500~2000). I'm using also DashCommand with the same settings as in LTP and it calculates the gears much better. With v14 I did not have these issues. On my RS4 with LPT 14, same settings same results as with DashCommand.
- when I change gears at higher revs than the ones mentioned above, there is a time gap of more than a second between the time I change gear and the time the new gear is displayed on LTP.
- the OBD rate on the Audi TT RS is 8.1 Hz but the OBD displayed data like RPM is really laggy... there is significant delay between RPM display and actual RPM in the car.