I had an eibach prokit on my 530d and wasn't happy with the drop so went to jom coilovers and was happy with them, they were surprisingly comfortable, I was expecting it to be rough like on the 3series but it wasn't.

Even the new owner was surprised by how comfortable it was.

The sport kit would be the way to go for look and comfort but they only make the sport kit for the 520 e39