MB's are pretty air tight, once me and my wife got into my W126 and closed our doors at the exact same time, the air pressure explosion prevented both our doors from closing all the way, we both had to open our door and try again.
The W123 is a great car, but after driving one around as a daily driver for 2-3 weeks earlier this year (our 300D) I decided the W126 is way more comfy and awesome.
I am getting annoyed with my engine though, its shaking the daylights out of me at idle in drive, I need to adjust my idle/rack damper, I've just been too lazy to actually do it.
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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)