I doubt that the sonic difference between a Mk3 and a 10R would be worth arguing about. However, that makes no difference to the marketplace. I am sure there is and will be hysteria about the 10R causing a flood of mk3's into the market which will lower the values. That's good for anyone with a calm disposition. That said, Chakster, where is the flood of Mk3's; I don't see it.
I had my slate plinth made to my specifications a few years ago. I bought it from Structural Slate in Bala Cynwyd, PA. They cut it to my dimensions (23x19x3) and honed it to have flat surfaces on both sides. I then had the hole for the MK3 cut by RC Waterjet in York, PA. For that purpose, I gave them a pdf file to program their machine. I think I got it off the website, Soundfountain, which is devoted to the Mk2 and 3. I did the rest of the work myself. I also had a wood base custom made to accommodate my slab. In the wood base, I installed a large rectangular chunk of brass (from OnLine Metals), which is drilled out and tapped to accommodate a brass rod. The brass rod stabilizes the bearing housing of the Mk3, a la Albert Porter's idea. I bolted the wood base to the slate by installing threaded inserts into the slate. The combination of cherry wood and slate gives some Constrained Layer Damping that seems to help. (I listened to the Mk3 before and after installing the wood base. Sounds better with it.)
I had my slate plinth made to my specifications a few years ago. I bought it from Structural Slate in Bala Cynwyd, PA. They cut it to my dimensions (23x19x3) and honed it to have flat surfaces on both sides. I then had the hole for the MK3 cut by RC Waterjet in York, PA. For that purpose, I gave them a pdf file to program their machine. I think I got it off the website, Soundfountain, which is devoted to the Mk2 and 3. I did the rest of the work myself. I also had a wood base custom made to accommodate my slab. In the wood base, I installed a large rectangular chunk of brass (from OnLine Metals), which is drilled out and tapped to accommodate a brass rod. The brass rod stabilizes the bearing housing of the Mk3, a la Albert Porter's idea. I bolted the wood base to the slate by installing threaded inserts into the slate. The combination of cherry wood and slate gives some Constrained Layer Damping that seems to help. (I listened to the Mk3 before and after installing the wood base. Sounds better with it.)