TDA7388 Sub-Mid Amplifier Design

I’m putting together a compact home audio system that runs a sealed-box subwoofer and a pair of midrange drivers from a single TDA7388. My plan is to feed the two bridged channels through a JRC4558 low-pass network for the sub, while the remaining two channels stay full-range for the mids... (Budget: $250 - $750 USD, Jobs: Audio Engineering, Circuit Design, Electrical Engineering, Electronics, Embedded Systems, PCB Layout, Prototyping, Signal Processing)