I almost did a Dinan package on mine but waited for the BMW Performance parts to come out. I did the exhaust and the intake last week. I had my Service Center order and install the parts. Here is the link for the parts
BMW North America
BMW North America
The first is the general site and the second is the exhaust. The price quoted on the link installed is exactly what my service center charged me for both components.
I will say I am very pleased with the appearance, the sound, and the added performance.