As a superior and more durable alternative to the Norton lapping stone, DMT has been recommended. Accross the web (and probably within this forum), the two most common references that I recall seeing for that purpose have been:
DMT D8C
DMT 325
What makes my brain hurt is that when I google under DMT D8C, Amazon shows what appears to be the dimensions of a Norton waterstone. DMT D8C 8-Inch Dia-Sharp Continuous Diamond Coarse - Amazon.com It resembles a waterstone in thickness, and is billed as (and appears to be) a "continuous diamond" surface, but unlike any waterstone it can be used dry. This is not what they call the "whetstone" (DMT 325), which by comparision looks very thin, and is described (as it appears to be) as a steel plate embedded with diamond. If this is steel, then I don't know if I would ever want to get it wet, therefore the name "whetstone" sounds rather mysterious. These appear to be very different products, although both are billed for "325 mesh". Perhaps it's the fact that both have that same grit pattern which is causing people to use DMT D8C and DMT 325 interchangeably.

Anyway, which is better for lapping with - is it the DMT D8C, or the DMT 325? Also, are they both about as durable?

Thanks.