[Pablito1702]

I finally got around to replacing mine after ordering the parts a year ago from thebmwminipartstore.com for a total cost of $79.82 including shipping

063-25-9-128-043 Hex Nuts (4) - $.38 each
063-25-7-164-978 Third Stop Lamp - $68.45
063-25-7-211-238 Springs (4) - $0.85 each

A few comments on the install. I ground down the metal tab with a metal file as shown in Dack's photos. It takes awhile but it does the trick and avoids any potential mishaps with a power tool.

I primed and painted the metal to avoid any future corrosion. For removing the plastic ridge on the lamp itself, I used a sharp wood chisel and made multiple shallow passes to scrape it away. But be sure to protect the rubber gasket around the lens that buts up against the ridge so you don't slice it by mistake with whatever implement you use.

The replacement springs are definitely a lighter gauge. I purchased a "deep" 8 mm socket based on others comments, but did not use. My regular 8 mm socket in 1/4" drive ratchet set worked just fine, as I didn't screw the nuts too far up on the posts before I felt it was adequately tightened.

In order not to drop the hex nuts when getting them started, I found it easier to insert the nut into the socket and spin the socket by hand rather than try and use my fingers. I was careful not to compress the springs too much by over-tightening the nuts. I stopped when the lens appeared snug and the hex nuts had approx. 1/4" of thread exposed below them. I probably could have tighten further, so I plan to check for any looseness of the lens after driving for a few months.