Has your mechanic...
...performed a leak down test? Often the most obvious reason for rough idle (leaky valves) is overlooked. Even on a relatively new engine (and your 95 with only 60K miles is NEW) valves can leak for a number of reasons. So have your mechanic check this out (if he hasn't already done so).
And enjoy your car. It is a beautiful piece oof mechanical engineering. Good luck.
1989 300TE "Alice"
1990 300CE "Sam Spade"
1991 300CE "Beowulf" RIP (06.1991 - 10.10.2007)
1998 E320 "Orson"
2002 C320 Wagon "Molly Fox"
Res non semper sunt quae esse videntur
Not in this weather!