I just purchased a Kenwood Excelon HU DDX790 to handle the lack of BT on the stock base unit. A friend of mine and I did the install along with the access ASWC and Satellite tuner. I think I got the HU, wiring harnesses, dash kit (not needed) and install instructions for $499. The Satellite tuner and ASWC were a bit extra. Here is the link to pics in my gallery of the installed radio:
Nissan 370Z Forum - Gadgetech's Album: Radio Kenwood Excelon DDX790
BT music streaming works well as expected. In regards to BT functions for the phone, you can do everything from the radio. My phonebook is on there, you can set quick dials or direct dial as well as dial by voice. With my Windows Lumia 1020 I get notification of a message and communicate with the phone to respond to text messages vocally through the radio.
This radio has a Pandora app which doesn't work with my Windows Phone (it isn't listed as a supported option in the manual but I really don't know why it would matter) but the audio streaming works well and you can skip ahead songs by hitting the FF button on the radio. It doesn't show album cover art though and I think this may be one of the few differences b/w the Pandora app and BT audio streaming.
I chose this radio b/c I've had an Excelon radio in the past with great results and I like the ability to adjust the panel button colors to match the interior colors.