The 740 is a great looking car but they are a nightmare if they have problems.
The E320 is a better car of the 2.

Also, the M104 engines of the W210 do not have the wire harness problems nor the Head Gasket problems.

Make sure to take a look at the spring pearches for rust.

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2010 W212 E350 Sport
1996 W210 E320 (220K miles)

Nikasil block= oil burner. Check for a rough idle, a sure sign that it's a oil burner, it can burn oil with no visible smoke.

My local indy refused to let me buy a nice 1997 for $3900 because he said he didn;t want me to hate him in six months.....