As above I got me windows rears tinted today on my Titanium silver E60 530d and it looks the danglies Well pleased with the job!
I figure I got a good price, £150 for all the backs and he came to me! That was cheaper than some of the companies I phoned who are not mobile ie drop the car off to them - which did not suit me whilst working away form home.
The guy who did mine was a spot on bloke, he got on with the job whilst I worked away in the office! I found him on this site. Can't recommend him enough.
I am pretty sure it was 20% I got, and the best bit is they are guaranteed for the life of the car from peeling, blistering and discolouring.
I'll put up some pics at the weekend Red!