(and actually next year you will find Chrysler motors in Mercedes)
Downix do you have a link for that?? ...Chrysler is in
a much better position to benefit technologically,
...and I still imagine you will NOT be seeing an
American designed and built engine in a Mercedes
(or I will eat my f-ing shoe, I promise!!

Already previously Chrysler-only features (such as polyheads) are showing up in Mercedes motors.
Well, the "polyspherical" head was basically
Chrysler's custom take of the "hemi", really nothing
special. Mercedes has had it's own "hemi" shaped
heads long before the "big three" (as well as other
niceties, like overhead cams/valves, use of light
alloys -even magnesium- and fuel injection (1954
300SL, or 1936 if you count Diesel injection...actually
you saw all of the above in the 300SL;)).
But Chrysler and Mercedes had been in bed long
before the "merger"...even in the '70's M-B used
some of Chrysler's A/C components. But my main
point is that you will not find a rebadged, American
designed and built Chrysler motor or chassis in a
Mercedes.