The tyre insurance works like this i think. You pay £390 up front and that "allows" you to have a certain amount of blow-outs in five years. I think its 5, but I stand to be corrected!
If you have run flats, sounds a good deal as they cant be repaired. Obviously M's don't run on run flats so if you budget on £250 a corner it makes sense. Of course I have only just joined the hallowed ranks of M3 ownership and not experienced shopping around for PS2's.....yet!!!!!
As far as the GAP insurance goes I managed to get them to stump up half the premium so very pleased about that.