I am still trying to do this (like I said I am no audiophile, but I did like the sound of these speakers and don't want to toss them out if I can fix them for cheap!).

Decided to go with this amp (based on TPA3116D2 and seems to work well according to some YT reviews), use this for a power supply, bypass the internal wiring of the sub and connect the sub and satellites to the amp.

Not sure if I am overlooking something, will find out in a few days and update the thread!