If the concern was replacing existing calipers with the same brand, that would not be necessary. Either ATE or Bendix will work, but the generally accepted advice is to keep the same brand on a given 'axle' or end of the car. I have personally never seen a set of Bendix units, as all of our 123's and 220D's have all had ATE calipers. Rebuilt ATE's from O'Reilly's have proven to be quite reasonably priced and reliable.

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150