Definitely keep the electronics, and use the original vehicle wire harness if possible. Most of the aftermarket harnesses use only minimum computer functions, and you'll lose a lot of the desireable features of the factory setup. You might need to fit the donor vehicle's gauge cluster, or figure out a way to incorporate the vehicle speed sensor into the system. Otherwise, the torque converter clutch won't lock in, and you'll get a constant "check engine" light indicating no VSS signal. A factory wiring diagram, and some time and patience should get you under way. Good luck!
Jerry