Thanks for the inputs. Never thought the sub as high priority (since I turn it down most of time), but now thinking about it, I often do come across movie scenes where the LFE was weak and out of place (immersion breaking). Makes perfect sense to upgrade it now.
A quick search comes up with an SVS PB12 Plus in my area for $800. Seems well-reviewed
here. Grab it or get something bigger, newer? One constraint is that I have only about 18" from the floor to the bottom of my screen, so it would have to be a side placement. Shouldn't be a problem, I hope.
I don't think I'll be able to find room to fit 2 large subs, at least without changing out the couch for a smaller one.
Sounds like nay on going prepro + amp, and maybe even mixed/nay on AVR update? Would you guys mind elaborating on rationale? After the sub, is the next step AVR + ceiling speakers, or will just AVR make a big difference?