The OBD adaptor I'm using is http://www.plxkiwi.com/kiwibluetooth/. On the Torque website there's heaps of warnings about buying a cheap OBD adaptor off ebay.
Yes, the thing behind the tablet is an amp. It's purely in as a replacement for the amp in the stereo that I removed, it's only temporary until I move house, then I will have room to install a proper amp in the boot. This amp is doing the job, but it's not all that powerful, and when the tablet is syncing to the tower, I get those noises through the speakers, I presume it's because the amp is right next to the tablet. I would recommend getting a proper amp, but if you must get one of these, search ebay for "mini amplifier"