Why sell the EP2500 and get two RMX1450s? Just get a 2nd EP2500 and that substantially exceed two RMX1450s.
Or, you can use the two RMS1450s on the subwoofers and use the existing EP2500 on the main speakers. I know you may not like the idea of using a 'pro' amp in place of your fancy mono blocks, but the chances are, the EP2500 is a better actual amplifier, measurably, and it has far more power for dynamics, no question.
And in practical terms; you already get approx. 125dB at 20-30hz with one EP2500 on those subwoofers. Why do you need 1 more watt of additional power, even?
-Chris