In a rack, with air circulate is always a good idea.
AVR was only an idea. Preamp or DAC with preamp. Better with balanced.
Better than cheap class D, yes. Cheap class D -> subwoofer, bad idea to full range at home.
Benchmark has better specifications except for the power but the PAS has good numbers (we lack independent graphics and measurements).
If you live in Europe I would try the PAS. If you do not like it, you return it within 30 days. To spend more money you will always be on time.
It will also depend on the kind of music you listen to. If it is the current commercial, so badly produced and with DR <10 there is little point in spending a fortune on the stereo, I say.
For multimedia, then the PAS or other cheaper ones will suffice. PAS for the front speakers.