20 just about every time for me. With the 3.46 rear end, it probably wont get much higher. My best is about 23.

__________________
'90 300SE 298k
-300K and it gets put into retirement.
'80 300D 255k Purchased new by family in 1980.

Had a:
1973 220 (gas)
1980 300SD
1992 400E