I really don't mean to hijack this thread; if you want a receiver, it is of course your choice whether or not to go and buy one. But let me tell you a story...
My Z9 recently had to have a minor glitch fixed. In the interim, I hooked-up my old Musical Fidelity Pre/Power amps. The thing is, the volume knob is a bit worn at low volumes. As a result, from time to time the 'dust' that's been rubbed off the volume causes an audible 'crackling' sound from the speakers. The noise isn't terrible, but I didn't like hearing it through my Missions so I hooked-up an old pair of Tannoy Mercury M1 bookshelves that I bought many years ago.
I cannot tell you how good the sound was with my room treated. I'll not deny that the sound was better with my Missions, but for a pair of approximately $210 speakers, and discounting the CD player/amp etc as contibuting much, the sound was unbelievable. If ever there was proof of the difference room treatment makes, for me, that was it.
You may wish to buy a new receiver for features you do not already have. That is your prerogative. But if it is for an improved sound over and above that which you currently have, then I truly believe room treatment is the way to go. It will breathe new life into your sound.
Regards