Hadn't really thought too much about either - but a friend of the wife was just mugged for her car keys, outside her front door 2 streets away from us -- and it's made me think!
I had the GAP insurance on my A3 - seems like a rational thing to do, but how about trackers? Assume they're going to make bugger all diff to my insurance but drastically improve the chances of recovering the car?
Lastly - I assume that going through the dealer for either isn't going to be cheap (albeit reliable and legit I would hope!) - would you go elsewhere?