300TE has lower axle ratio than 300E, so it's not just the aero and weight that make fuel economy different from sedan.

The W124 is the last of the "dinosaur" E-class. A nice W210 wagon with the new V6 and the 5-speed transmission will turn maybe 2700 rpm at 75 mph versus the 3500 rpm yours turns. The L-Jetronic is better than K-Jetronic, too, and it's a lot more efficient engine.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles