Hope this info helps, I installed mine a while back and was asked about how to install it before.

I looked at the oem one for a while trying to figure out how in the hell I was going to get it off. Then studied the new one. When you look at the new one, you will see there is a lip extending from the bottom and the right side at the top kinda hooks around. So figuring it had to be popped off from the left, I started on the left side near the bottom and pry-ed it out gently. I then proceeded to work up that side until the bottom part was loose (barely). Then, I pry-ed the top left part and worked it back then left then up and it came off.

To put the new one on, you will want to start with the top right hooking it into place, then the bottom indent, finally snap in the left side.

This rambling I wrote will make more sense when you see the back of the new one. I was able to get the old one off without damaging anything. I was so aggravated after getting home from BMW that I did it in my driveway after getting home. The only tools I used was my finger nail (for the bottom left side) then my trusty p-38 that was on my key-chain (for the top left side).

Hope I was able to help! Good luck, let me know if you need any pics of the back side of the old one.