You have 2 two tops, each 8 Ohm, and 2 subs, each also 8 Ohm?
My understanding is that if you plug one 8 Ohm sub and one 8 Ohm top into one of these Skytec passive crossovers you end up with an overall load for that system of approx. 8 Ohms. Which you can plug into one channel of your Behringer, you'll get about 165W RMS according to the spec less a bit in the crossover.
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