While I don't personally know their QC standards & guidelines I can also say that there's a high probability that a good amount of warranty replacement parts through BMW OEM is due to improper installation as well such as rolled gaskets, incorrectly torqued hardware etc. I can tell you with certainty that If I send a rolled VCG back for warranty repairs 99/100 they won't say it's because it was installed incorrectly. Better to take the loss and send a new gasket.