If you get a 4 channel and plan to run it in two channel mode all you have to do is get a set of RCA plitters or Y cables. Run it to the amp. It also depends on your amp too. I have a Cadence that can take the two inputs and make the amp run at a 4 channel operation.

1998 Contour SE V6 2002 Focus ZTS 1980 Turbo Trans-Am