Just a quick DIY for installing sideskirts to your mk4. Oem sideskirts install slightly different, due to having clips that attach at the pinch weld. Still the same concept.
3m double sides tape 1/2in. Size atleast
Acetone or other cleaner
Clean the backside of the sideskirt where the tape will stick. You want the tape about a 1/8-1/4in. Below the edge.
Apply the tape.
Now clean the area where the tape will stick on the rocker. Clean the whole area well.
Peel the backing back like so.
Hold the Sidskirt up and lightly stick it to the rocker. Make sure you are able to pull the backing on the tape. Also some tuck the skirts under the fender liner or you can go over top of it. Just personal preference.
Now carefully pulling the backing off the tape and sticking the sideskirt to the rocker. Be sure to make sure its level the way. Its a good idea to have a friend help level it and hold it while you remove the backing and press it in place.
Firmly press to get a good adhesion.
The sideskirt should sit low enough to have about a 1/4 or so to the door opening. This way it won't get caught when someone climbs in and out of the car.
Secure the front with 2 screws to keep it from twisting.
Do the same with the back.
You will probably have to drill holes in the sideskirts for the screws.
Step back and admire your new look.