>>Dimensional lumber is still referred to with the Imperial system in Canada.
However, 1/2" plywood is referred to as 50mm (millimeter)

OK I couldn't resist ... what kind of math makes 50 mm = 1/2 inch?? ... anyone into cycling (US) is pretty much forced to learn metrics

That said, I'm interested in the discussion of needing a sub with M80s -- I often thought that one could get away without a sub for HT with M80 fronts considering their frequency & power-handling specs and even moreso for stereo. Or would you be looking for the sub amp to push the base that much more?