speakers for classic receiver

@trent77-

                         "Take the Focals and enjoy!"  +1

     Back in the day: Sansui did many more things correctly (regarding sound quality), than almost all of the Mid-FI stuff out there, outside of *somewhat harsh highs.

      Take those Focals home and listen to them, with your favorite music, for at least a couple weeks, before doing any other auditioning.

      Outside of the OHMs, I can virtually guarantee; what has been recommended *will fatigue your ears, in short order.

      If you're still planning on auditioning those other speakers, afterward: don't bother, unless they can be listened to with YOUR OWN source(s) and receivers, in your own listening room.  

                Otherwise: you won't have a clue, as to their performance at home.

                                                    Enjoy the journey!

By all means, jump on those Focal Aria 936 if they're free! Those are $5,500 a pair speakers! You'd be out of your gourd to pass up a deal like that! I spent around 3  hours of serious seat-time with a pair of those speakers powered by a McIntosh MA5200 and a Luxman (can't remember model number) and they sounded outstanding! Either of your vintage Sansui receivers can easily power those but I would go with the G9000 because of the additional power & juice. I still have a vintage Sansui receiver I purchased in 1972. As for wolfie's " The Sansui’s are not great amps, though." remark, he either has never heard one in good shape or he needs an audiological evaluation. Go for it!

Grab these up. 
Don’t know what the deal is, but these sell new for around $2700 each, and I see some “open box” as low as $2400 each. 
Happy for your good fortune!

92dB sensitivity is on the high side, and if you don’t drive  your amp into clipping, will sound quite good. If clipping, you will hear it as strain/grain, and if pressed further can damage speakers. 
These will sound stunning with current gear, but will begin your journey to higher-end amplification. It’s a grande journey. 
Consider a nice self-powered subwoofer like a Rel T/x series to ger the really low bass. 
The Focals are on my very short list to replace my mid-80s Kef Reference 103/3, and that will be hard for me. 

"...I would go with the G9000 because of the additional power & juice."

                                                      +1

Hello,
It sounds like it will push the Focal’s just fine. Typically older stuff had two sets of speaker posts. Even if the Focal’s dip down to 4 ohms you will be fine. I would not bi-amp off the Sansui. Stick with one set of speaker posts and use jumpers on the speakers if you need them. Due to the deal your getting its worth it. Later you can upgrade the amp to get better headroom and sound stage. You might be able to add an amp to the Sansui and then add a better preamp like a Rogue tube preamp with a SS amp. Go for it. Speakers make a huge difference in your system.