I would use OE for both. I've replaced just one upper bearing for damage and it was after I allowed a shop to install the first set of springs over ten years ago. Not sure if they did something but they were not taking responsibility for it so I just went and replaced it.
I just added a fourth set-up of springs, the first being Sportlines, and I always add new OE bearings when I do this. Perhaps the next time I remove the struts, I will replace the upper mounts as well. I too have B8s so it may take some time before the need to do this arises.
As far as a bearing upgrade goes....I don't think it is necessary and thus unavailable. But I again would stick with OE or the original maker of the OE bearings before trusting just any OE replacement part.