Also when you put the drives windows down, listen for a knocking or a ticking noise. Hard to explain but you will hear it. This is a sign the window mech is going. The motor will be OK just the mech, we bought a new one for around £100 from BMW and I fitted, pretty easy to do, getting the door card of is the hardest part as they are really well built. Get one with as much spec as you can, HK is really good in ours (Harmon Kardon) and the bi xenon lights are really good too. Auto lights, auto wipers, climate control, air con, steering wheel control, cruise control, split folding rear seats, parking sensors, bluetooth phone and no doubt still more. Really nice car, best I have bought. Also check the rear number plate lights work and the boot release. These are known to fail, had to replace ours as one of the bulbs would not work. Found the part cheap but if you was buying new from BMW your looking at a couple hundred including paint.