Yes and No. It depends on the quality of the resin parts and the car I am using them on. Of the brake components I use the control valve the most due to the quality of many plastic ones.
Surprised to hear about the casting defect rate. I have attempted to mold them and as you stated difficult to extract from the mold. I find even more difficult is to fill the mold with proper amount of resin to get a good part even if vaccum chamber and pump used.
