We have the 'pop out' holders on my wife's new-to-her 98 C230. I noticed in the brochure that the Sport version has a bin in place of the holders. I don't know if it will adapt to your 190, but I think I am going to loose the pop-outs real quick!
Also, Crutchfield supplied a nice plastic bin for our Toyota Celica when we replaced the double DIN factory stereo with a single DIN Kenwood. You might see if they have a bin that would work.
2003 Firemist Red/grey leather SL 500
2015 Palladium Silver/black mbtex GLK 350
1987 Smoke Silver/burgundy mbtex 300E Sportline (SOLD)
Click to see 87 300E