Like many people, I recently decided to add a set of M3 sideskirts to my car. You can buy them from practically any vendor and they're a relatively inexpensive way to add some more aggressive styling to the car. When they arrived on my doorstep, I decided to look on this site for a guide to installation. I found a helpful video that showed someone installing the skirts, but it still left me with some questions. I was unable to locate a detailed guide with pictures, so I decided to make one myself while doing the install. This is pretty easy to do (and coming from me that means a lot. I'm all thumbs.) Enjoy!
Remove the door sill. It literally just pops off. It makes a loud (kinda scary) cracking noise as it breaks loose, but you won't break anything. Start in the middle, by lifting up under the "BMW" lettering and working your way down to one end and then the other.
Some of the white clips may come off with the sill, but most will need to be yanked out. See below.
Remove the black plastic clips holding the skirt to the car. The center piece lifts up and out very easily. Remove them carefully, making sure not to scratch your paint. Leave the grommets (the black pieces left behind when you've removed the center) in place for now.
Set these aside too. At this point you should have two piles off to the side: white clips and black "pins."
Remove these two screws from the rear wheel well. You'll need an 8mm socket wrench.
Time to remove the screws along the bottom of the skirt. They use a "hex" or "allen" wrench.
Pull the old skirt off the car. First, head back up to the door sill and lift up the edge of the skirt. Those black grommets we left in place before will pop out easily, just pull straight up. Set them aside, since you'll be reusing them on the new skirts.
Pull the entire skirt up and out, and it will pull away from the car. You will notice that there are four more clips holding the rear aspect of the skirt in place. Pull straight out and they will break lose, usually with a loud cracking sound. Again don't worry, you aren't breaking anything.
Three piles off to the side.
The screws you removed from the underside with your hex/allen wrench will be used in the next step and, if you're doing the install alone, you'll want them within reach. I kept mine on the ground next to the car instead of putting them inside on the floor with all of these.
Put the new skirt in place. This can be a pain in the butt, but take your time and don't get frustrated. This is tough to do alone. I wish I had a helper, because this step would have been a whole lot easier.
Things to remember:
Each screw that holds the underside of the skirt has a "base" that it needs to screw into. Your goal is to allign the holes in the skirt with these bases, so the screws have something to bite into.
The undercarriage liner goes OVER the side skirt. you need to wiggle the skirt between the "bases" for the scews and the liner. This takes some effort. The skirts are a bit large and unwieldly, so this is why it's a pain to do it alone. Having one person at each end of the skirt would make this job a lot easier.
When you have it roughly alligned, put a few of the screws near the middle in place. This will free up your hands to allign the ends, as you will no longer have to hold the piece in place.
Slowly but surely, wiggle it into place. Getting the skirt to slide between the undercarriage liner and the screw bases is the hardest part, but you can do it if you're patient. I suggest doing one side at a time, so you can go look at the other side if you forget how it's supposed to look.
Reassemble the door sill. First, pop the black grommets back into the holes, then slide the black pins back into them.
Next, slide the white clips into the slots on the back of the door sills. Replace the sills by first snapping the middle clips into place, then doing the ends one by one.
Enjoy your new sideskirts!!