As long as you don't have any originality issues because the actual colors no longer match the chassis plate, go for it. I have no problem with two tone W113s, but then mine came from M-B that way!
Bear in mind that it would be far easier to change the hardtop color than to change the body color. Remember that the hubcaps should properly be the same color as the hardtop, so you should repaint them as well if you change the hardtop color. You would just about have to take the whole car apart to properly change the body color, as the dash, engine compartment and door jambs would need to be repainted - and for the paint to stick all the nooks and crannies would need to be cleaned and prepared. By the time you've done all that you'll probably be well along with a complete restoration!
The good news is that you have a whole rainbow of contrasting colors available to you that will look super with a 181 Light Beige body color. Black, and various shades of Brown, Green, Maroon, or even Blue will work well with your body and interior color combination. I'd favor Black, Brown or Maroon myself.
- Mike Hughes -ô¿ô-
1966 230SL Auto P/S
Havanna Brown (408)
Light Beige (181)
Cream M-B Tex (121)