Aren't they only about 6.5"?
If we're still using original style upper strut mounts, then spring diameter won't be a limiting factor. But once you change to a camber plate that allows for more negative camber, then you can run into problems. The big diameter stock spring can hit the inside of the strut tower, and when that happens, you'll notice the steering doesn't like to re-center after a turn because the spring is rubbing against the tower and trying to turn, but there's resistance. No big deal, easy fix, but it does limit the max negative camber.
2.5" ID coilover springs with camber plates give more range for negative camber adjustment, and many more choices of length and rate.