I like What about cutting off the tabs and installing some type of nice inserts to cover up the cut? You may be able to extend it down to act as a grommet as well.
Either that or use some roll bar padding...or make a cross bar bolted with some nice chrome hardware. Now you got me thinking of a new winter project

If you get a chance, can you make a drawing with some precise measurements to make a template for the cutout. Thanks

BTW the accessory chrome bars for the SLK don't appear to have those tabs