123 Brake Caliper Rebuild

[seo]

I have a 1983 123 300d sedan coming out of winter storage with a bad caliper. Looks like one piston is hanging up. A local Mercedes mechanic has advised me that:
1) They're not easy to rebuild
2) ATE are much better than Bendix

Looking around for rebuilt replacements, I come up with "A1 Cardone" as the main source for rebuilds. Some are specified as being ATE, others as Bendix, some are not specified.

So my questions are:
a) Does anybody sell rebuild kits? Are these harder to rebuild than Girling calipers?
b) Does Cardone sell good products?
c) Are ATE really better than Bendix?
d) What are the Cardone calipers that aren't specified by who the maker is?

Thanks
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