TopDMC, the intravee / Alpine set up is dead easy to fit, just fiddly threading wires. I managed it and I am not technical at all. As for second hand - generally the bits sit behind the seats in the boot, and in my case the Alpine unit is under the passenger seat. They don't get abused where they are, and the only thing you may need to do is update the firmware on the intravee, which I also managed - there's loads of instructions. You can get very techie with it if you want to - the threads scared the hell out of me too - but if you just want to install and forget then it's very simple.