I've seen a ouple of upgrade kits for the Planar 3 on ebay - The
manufacturer seems to be SMTECH based on the email contact address.
They claim to reduce motor vibration, improve neutrality etc by
replacing the platter with a thicker acrylic one and a silicone rubber
mat, along with some other tweaks to the bearing and motor housing. It
seems to make sense, but does anyone have direct experience of these
upgrades and do they make a significant difference ?