If you need more oomph. I would invest in better subwoofage. The 8012 is a great AVR and I think you’ll like it a lot.
As far as the cubes, you can try them just for fun, but they’re basically useless. The frequency response is small and wonky and the output won’t be very dynamic. If you try them, I’d look to replace in short order.
Subs from Rythmik, HSU, SVS, and monolith would be a good place to start looking.