I have Dinan Springs, and camber plates installed, my car is a 2011 E90 ZHP EDC. I also have the anti-roll bar, and rear toe links that are not installed yet. I did feel a tiny bit increase in stiffness, but overall the car is almost like stock.
I haven't tracked the car with Dinan suspension, but I would imagine one would need better dampaning control than EDC.
I'm planning to upgrade, so my dinan stuff will be for sale soon.