I need some info on how exactly you guys did it. I read somewhere that somebody used strips of steel. How were they arranged? Does anyone have pics?

Thanks for the help guys.

I just did mine the other day. I used 1/4" bolts with large fender washers on either side (top and bottom) with nuts to hold the panel in place. The metal panel is just the right size to allow clearance for the bolts to slip between the panel and the roof edge. I used four total - one in each corner. I then used a larger wire size in my mig and did a series of 1" welds around the perimeter of the panel. When that was finished I just used an automotive caulk to fill in the spaces (used duct tape on the underside of the crack to keep the caulk from oozing through). It seems to work really well and is very strong.
When I was finished I saw a guy on Ebay had a carbon fibre panel that installs from the underside of the roof. It has a large flange that you could just screw to the supports (doubled metal) around the sunroof. The panel looked to be a good solution but at a couple of hundred dollars was more costly than my DIY fix. Hope this helps.

I did similar to Kneedrager. I welded short filler pieces in the void between the panel and the surrounding roof cut from 3/16 steel bar. Then once that was done I used clear packing tape on the underside and filled the gap with JB Weld. Then once that was hardened, removed the packing tape leaving a nice somewhat finished interior and ground/sanded down the rooftop. I still have to do some minor filling on the roof, then will finish prep and paint.

-Tom

here is a post of my pics -- be aware -- my upload connection is not the greatest at the moment -- working on that...

http://www.xtreme-g.com/Project%20BMW%20M3%20Photos.htm