I think Lemforder mounts are fine, they are the OEM supplier. You just have to realize even with strict quality control, once in a while, a bad part goes through. I bought new brake discs from the dealer for my 190E (were much cheaper than any decent aftermarket brand actually) and one of them was warped. I just told them about it and they ordered another for me and exchanged it. This is why some people buy a well rated car like a Camry or something and it turns out to be a lemon, maybe because a solder joint didn't come out right when the ECU was manufactured or the wiring harness was accidentally damaged by a worker having an off day.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.