I would look at some of the jl audio amps some allow separate channel switching, I put a 6 channel in the silverado and another 2 channel for the subsThe ohms are stock, so i would imagine they know that.
Im tired of messing with it for hours on end and getting nowhere, so im done with it and will be looking for a small 4ch 60w x4, 2/4ohm amp.
it supports 2ohm, 4ohm, channel separation, level control for each channel, etc
jl audio xd600/6v2