The amp has balanced inputs (4 rca inputs) and can be bridged down to 2ohms on each channel. Therfore giving you the option to have the fronts bridged down to 2ohms, and the rears bridged down to 2ohms... The amp will put out 150 @ 2ohms each side.. so, 75w for each speaker.
My lower cost 4 channel amps meeting your power requirements start at $139. I do have cheaper 4 channel amps, but the quality is unknown, and I don't recommend spending less than $100 on a new 75Wx4 to 100Wx4 amp.