I bought a used one from a part out. I used tape to line it up then made my template and drilled away. The factory one comes with a light and typically the trunk has the plug in place so you can plug in the new spoiler. IIRC spoilers are a dealer installed item so the cars came from the factory prewired so the dealership employees could install them easily. One nice thing is that once the spoiler plug is connected it overrides the rear window break light so it doesnt light up when the spolier one does. At least on My P11 it does that, my P10 had a spolier so I couldnt say for sure.