This is not an answer to ur OP but I'm selling my Syn 6 and Syn 4 amplifiers.
IMO if you buy the pair of Rev 410's and want to be in the "over the top" category I would buy the Sinister 4 amplifier for the tower however the Syn 4 that I have on my pair of 410's is more than enough but I'm silly
Asking $500.00 shipped for the Syn 4 USA only
Asking $650.00 shipped for the Syn 6 USA only
I'm going to have to sell the Syn's before the wife will let me be Sinister!!