They did my 3 series for me around Christmas, and I think the cost depends on the amount of adjustment required. Can't remember how much it was, but certainly a lot less than you've been quoted I used them on a recommendation, and wouldn't hesitate to recommend them myself now.
Mine are pretty adjustable. I can't find the receipt from a few years ago but I think maybe £80 rings a bell. Just wanted a view of the realism of £150!
I paid £60 for my old 528i, and it came out like a new car. A new car that loved pulling to the right. Took it back and it came out and felt amazing, totally transformed it. Highly recommend them.
