@drlou77 I wouldn’t.
What are your expectations with this switch?
With an actual $600 price difference you’re paying $900 for 300 more switching amp watts and a 2" larger woofer (the radiators are both 12") and a manufacture rated 1 lower -6dB Hz all for a subjectively small 15’X12’ room. Would this dust up some potential significant other aggravation?
I’m fairly certain there’ll be a very slight difference but a $900 improvement? That’s your consideration.
After my experience with a top line REL the only rational for remaining in the REL -6dB sub-bass woofer Eco system is incredibly restricted location space.
@awise1961 Were your Grotto’s positioned in the same location as the pair of 212/SX’s pictured?