Buying new bookshelf speakers

[JoeE SP9]

good stuff. There Is always jbl paradigm and klipsch subs floating around CL

Are the HSU subs any good?

Yes. Some are very good.

And are the MMG's bi-ampable??

Yes. However, it requires enough skills to bypass or rewire the crossovers. Theoretically any thing that is not a single driver speaker can be bi-amped.