The lower dash in your W126 is very similar to my W116, so they probably attached the same way. After I remove the screws it just pulls off. There are a couple of plastic tabs attached to the carpeted piece. They go into metal clips in the dash itself. Like I said though the carpeted panel should just pop out if you have removed all of the screws. Like everything you do for the first time, take it slow. I am sure alot of us have yanked on some plastic part just a little to hard and snap.
1994 MB E320 Coupe (199,500 mi)
1992 MB 190E 2.6 (173,000 mi)
1983 Porsche 911SC (148,000 mi)
2004 Volvo V70 2.5T (198,000 mi)
President of CT/Westchester Section