If they just bridge each channel of a KSA250 to make an MDA monoblock, then your better of just staying with the KSA250, as bridged amps don't have the same bass control, as their damping factor is reduced as well as other things.
You could get another KSA250 and then bi-amp, that would be a better way to go in my opinion if your speaker allow it, I think the Aerial 10T do.
Cheers George