I have the Symphony 2 head unit with the 6-disc in dash CD changer with XM Satellite radio (which I don't use). I also have the stock (I think) bluetooth interface that allows me to make/receive calls through the stereo.

I'd like to be able to connect my android phone and iPod to my stereo, and still be able to use the steering wheel volume/song selection buttons. What are my options?

I've been doing some digging, and so far I've found these options:
Dension Gateway Lite BT - GBL3xxx: Gateway Lite BT | A2DP | Bluetooth handsfree calls
Dension Gateway Pro BT: Gateway Pro BT | Bluetooth handsfree all-in-one interface | USB music playback
or
GROM-USB2P-AUD: http://gromaudio.com/store/usb_adapt...r_digital_inte rface.html

Are there any other methods/adapters out there I should be considering?

Does anyone have any opinions on which of the above is better?

If I connect my phone via bluetooth to play music, is that going to cause a problem with the existing bluetooth phone interface? Is this an either/or scenario, or does the bluetooth offered in the adapter duplicate what I already have?

Will I have to disable any functionality on my stereo in order to connect one of these adapters?

Are there any other parts I'd need to get to make this thing work?

Thanks for reading!