I installed the molding. There are some details that I would have useful if instructions had been included. I'll pass this info on and hopefully it'll be useful to others.
The molding I received already had a bead of black glue or silicon running inside the channel of the molding. When I took it out of the package, I started noticing I had black tar on my hands. I didn't know where it was coming from until I looked closed at the molding. So, buyer beware: sometimes this part ships with the glue bead inside the channel.
With some trial and error (which is not good for a job like this), I learned that it's probably best to start on one of the top corners because that corner will tend to rise up if it isn't seated really well. And if you've already seated the side part, then it's impossible to pull it down to make that corner tighter. I had to pull it back out and in so doing, the corner of my brand new cowl developed a tiny tear. I will fix it later, but it was disappointing.
I also didn't realize that there's basically a little outside channel that runs along the sides. This is another reason I thought I had the wrong part.... Once it fits in, though, it looks right.
So, once you get one corner seated right, start seating some of the side molding, then stop. Now start seating more of the top molding. This is because it's all a little loosey goosey until it's sitting right and if you've done the entire side, you might realize it's not seated quite right.
Then, make your way across the top continuing to seat it. When you get to the corner, it should fit just right. Now go check the first corner to see if it's still seated right. If so, you can either finish that side molding or go to the other corner and start seating some of the side molding. If both corners are tight, you can proceed to doing more of the sides.
Here's where I ran into trouble. I couldn't tell if the molding was supposed to go on the outside or inside of the cowl. I switched a couple of times and, to be honest, I'm still not sure which is the right way. I believe the cowl should be on the outside. It's not a perfect fit and I was surprised by that. I'm using OEM parts, so they should fit exactly right.
The first picture shows the cowl on top of the molding....
This second one shows the top corner fit...
It also seems like this part looks different from other Z4 moldings. The ones I've seen like like just one piece whereas mine looks like it's got a channel on the sides.
Does this look right to you?
