Not sure about their injector cups, but I bought a Dorman window regulator for my wifes car once. Had to replace it a month later, Dorman warrantied it out. It lasted two months. I went to the dealer and got one, paid a lot more for it, but when we sold the car three years later, it was still working.
Give one of the vendors here a call. Cups aint' that high.
I would hate to have to go back in a month to replace defective injector cups. I can also remember when Dorman made really good low cost replacement parts.