~$4,000 home theater + music system?

The PSB Imagine T2 should not be used with that Yamaha receiver. Stereophile's measurements on the speaker showed a minimum impedance of 2.4 ohms with a severe phase angle in the mid-range. It is recommended that the speaker be used with an amplifier that is stable into a 4 ohm load. The T2/Yamaha combination would likely result in damage to the Yamaha. It would be best to only consider 8 ohm speakers to use with the Yamaha.

A couple years ago my brother asked me a similar question. Given his limited budget and inability to hear many systems in his area, I recommended he try some speakers from Aperion since they get very good reviews and offer a 60-day return policy. The main reason I recommended them was that they offered my preferred 3-way center speaker with the silk tweeter mounted above a dedicated midrange driver. BTW, he too is using a mid-level Yamaha AVR although I can’t remember the model offhand, but that these speakers were around 89dB efficient and don't drop much below 4.5 Ohms was another reason I thought they'd work in his situation.  To be honest, I knew they’d be more than fine for him, but I was skeptical if I’d really like them (not a fan of Kevlar drivers in general). I have to say these speakers are very impressive indeed. He has the previous Verus models, and for both 2-channel and movies I have to say they sound superb. What most surprised me was their clarity without harshness along with a surprisingly deep and holographic soundstage -- not what I was expecting at all. And the center channel is superb. None of the muddiness or off-axis anamolies I hear from most centers, and the dynamics keep right up with the towers.

But, if it’s me I’d make a couple changes. I think the cheaper Intimus 5Bs (or probably even the 4Bs) would be fine for surround duties, so I’d save $ there. Also, I’d go with a sub from SVS, Hsu, etc. instead of an Aperion sub because, dollar for dollar, I think you get more performance. IMO, you just can’t do home theater without a decent sub. Past that, hey you have 60 days to see how they compare to your Snells. You might find they surprise you as much as they did me.  Hope this helps and best of luck in your search. 

Thanks again for these detailed comments and suggestions. I'm learning about issues I wasn't even aware of, which will reduce the risk of me doing something dumb.

Your room is almost square, consider 2 smaller subs instead of one big one, and do the 'clap' test to see if you have any undesirable reflection points.

I got rid of my upgradedititus disease by going to a 4 sub system and a few sound absorbing wall treatments

Good Luck!