They share the same engine but not the trans. The w124's were relegated to the 4sp auto while the W210's had the 5 speed.
95 E320 Coupe Black - 70,000 miles with Parchment interior. Stock through out
93 400E Dark Blue - 65,000 miles Sold to my dad
86 300E Gold(yuck!!!) 126,000 miles- Sold, a really fun car with a lot of memories