Don't want to make duplicate posts, but for those who don't follow my project thread, here is an update on the KW coils.
I got mine fitted today and they are pretty much as low as they will go!
The good news for F56 owners is that I can confirm that 18x8 ET45 with 205/40/18 tyres DOES NOT need a spacer (with KW coils at least, I can't comment on the BC's.) The bad news is that this set up is pretty much as aggressive as you can really go without encourtering unesscary headaches with fitment.
The fronts rub slightly on full lock when negotiating heavily cambered roads / drives at medium to low speeds, but its fine everywhere else. This will be solved with camber plates as and when they are available to order. Camber plates will be essential as currently I can only get -0.4 degrees camber with the stock set up. The rears don't seem to rub at all and I've had -2.4 degrees of camber dialled in, which obviously helps.
Pictures:
My driveway is rather difficult to negotiate now
