I had a '93 300TE with the 104 3.2 litre 'on trial' for a bit and I too thought the engine was very noisy compared to my 103-powered 300E, almost to the point of it being annoying. Went like stink though

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1993 320TE M104
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past:

1983 230E W123 M102
1994 E300D S124 OM606 (x2)
1967 250SE W108 M129
1972 280se 3.5 W108 M116
1980 280SE W116 M110
1980 350SE W116 M116
1992 300E W124 M103
1994 E280 W124 M104
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"music and women I cannot but give way to, whatever my business" -Pepys