I don't think the Dinan springs will give you the drop you are looking for. I had the sport suspension on my ride and I was blow away by how high that thing sat. I went with ACS springs. The cars drop is perfect and it handles how you would want it to handle. Lower to the ground and eliminates boat feeling. As for the comfort of ride it did not change. It's not a harsher ride at all. Just as smooth as the sport suspension I had before so it was a win all around. I highly recommend.
2012 550i - Space Gray - M Sport - 20" Vossen VVS CV2 -ACS springs
RETIRED - Space Gray 2009 528I