First, I sold Quad in it's heyday. Had my Akai since Feb '73. First Quad piece I bought. Got it new. 50 years old. Still works? You bet!!!!
Whatever you do, get it refurbished!!!!
I have had two RS 858 Technics. Better sound, plays & records Q8's in Quad. Still have one, and another play only Technics RS-847. IMHO, both sound better than regular panasonic models.
Forgive me, but I believe Technics & Panasonic all the same motor. Seems like it. Motor is undersize for Q8, basically a single Q8 tape is as big as a double length 2 ch 8-track. NEEDS MORE TORQUE TO PLAY Q8.
First deck I bought was Akai CR-80DSS. Records & plays in Quad, too. Only other deck that does. Great motor & adequate torque!! Tonality a bit different. Better bass on Akai, better highs on Technics. Both sound better than the black Panasonic.
Want to only play Q8? Try other brands like Sony or h/k (same Q8 deck as Sony.)
Want to play and record on Quad?? GET THE AKAI!! you'll pay more. It's the best built, but not as much curb appeal or creature features. If you compared them by weight, you'd see what I mean. Akai has a bigger motor.
I have nearly 400 Q8's. Akai still works and slows down less often and nearly never. Bigger motor. Had a lot more use, too!