I forget the centre bore diameter. If it is too small you can get the wheels machined. If it is too large I recommend you have aluminium hubcentric rings made as they are better than nylon ones.
I cannot guarantee that the wheels won't fit. What I do know is that 17x7" can have a max offset of 30-33mm depending on bead design. Thus going to 7.5" means an extra 6mm to deal with. So on that basis I was just erring on the side of caution as 10mm offset plus 6mm width =16mm = 15mm spacers not enough. But as sometimes you can get away with 33mm offset, maybe you'll be alright.
Either way it'll be a very, very tight fit. I'd try the 15mm spacers. On the rear this will mean only very slight rolling of the guards, and then if they don't fit on the front get 25mm spacers for the front.
You would also probably be OK with 8mm spacers on the rear, but they would tuck inside the guards too much for my taste.
Don't forget with spacers (especially15mm+) you will need to buy longer stud bolts or replace the bolts with hub studs and nuts. You can buy the former from BMW and both from the web.
This may help you.