Specifying only OE bearings means that you are buying bearings made to Japanese quality control standards.
Specifying only OE bearings means you are fitting the same standard of bearings that were deemed good enough by the factory when your machine rolled off the production line.
The question is, why would you order any other make when fitting them to your engine? Well, you probably wouldn't.
OE bearings means OE Japanese quality. Have you thought about trying this gasket sealant: 08CRAHLG120G for a more professional result.