If you hear any motor noise at all, there is a problem. Period. I would call the dealer and discuss it. (Is it new?)
Assuming you have already made up your mind to upgrade, and you are just putting feelers out there :) I would recommend the RM5SE. I have the Xperience and I LOVE it. For the reasons you mention, too. The cf tonearm is astounding and will mate with very high end cartridges. The optional speed box is reputed to be a nice upgrade, too, but I did not need it for mine - is very stable without it.
Assuming you have already made up your mind to upgrade, and you are just putting feelers out there :) I would recommend the RM5SE. I have the Xperience and I LOVE it. For the reasons you mention, too. The cf tonearm is astounding and will mate with very high end cartridges. The optional speed box is reputed to be a nice upgrade, too, but I did not need it for mine - is very stable without it.