Nice, and a bit of a bargain. Can I ask, how do you answer an incoming call - can you do it without touching the phone ?
I'd try and make a better connection on the live wire if you can, solder / heatshrink or even a crimped bullet connector.
Great idea though - I'm using one of those plug in cigar lighter types that connect over FM to the radio - it's a bit rubbish tbh.
Cheers,
Mike.