Subwoofer with the center channel

[SlumpBuster]

I was possibly thinking of getting some cheap 8" sub on ebay and replacing the driver with a TangBand sub from Partsexpress or just building one from scratch.

Well, I can vote "yes" for that based on the fun factor alone. Too many times people forget that this is supposed to be about having fun, not just a search for "perfection" whatever that may mean.