Depends mate you need to get them on first and see, I have 30mm spacers on mine and they stick out slightly beyond the wheel arches with them which may affect MOT and more annoyingly means the sides of the car a permanently filthy! The other thing to consider is that wheel spacers will wear your wheel bearings out quicker, how much quicker I don't know..
That sounds right, S. If you take a look at the rear of your LR with the new wheels fitted and compare it to the old pic, assuming that I am judging the ingress of the steps correctly, the you're looking at a definite change.
It could be a reduction of 10 to 20 in all honesty. If you ever get the chance to find out the actual figures then I would love to know.