My son rides regularly in the wagon. He's the reason I got a wagon rather than a coupe. There's room. THe infant seat takes up more room than the forward-facing seat. I put the kid seat on the passenger side. It does limit the seat adjustment for the front passenger. I wouldn't be that comfortable, at 6ft, sitting in the front passenger seat for very long. But my wife never complained during 5hr roadtrips, etc.

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1982 240 D, 308,000 - 321,127 miles (sold)
1982 300 TD,166,500 - 226,000 miles
1998 E 320, 120,000 - 144,000 miles
2005 C 230 K, 26,000 - 77,000 miles (sold)