Search this forum for "Bluetooth" and you'll find a slew of threads reporting issues with BT on the TP2 -from headsets to in-vehicle syncing. Looks like the biggest issue is that HTC went with the widcomm stack instead of the tried and tested MS stack.
There was this
thread on U-Connect for instance
And this
one on BT in the car
And this
one on the widcomm debate