Eric, you need to read my reviews (see below). Do not under-estimate what QS10, and in general v4, will do for you if you don't have v4. Moving to v4 is a much bigger upgrade than a new receiver or amp. That includes your 500. The sealed subs are the real deal!

QS10: very first review
https://www.axiomaudio.com/qs10-surround-sound-speakers

Fronts: scroll down to holography and black magic
https://www.axiomaudio.com/reviews/index/list/product/930/

Center: very first review
https://www.axiomaudio.com/reviews/index/list/product/27/

Sub: the Might from Dwight
https://www.axiomaudio.com/reviews/index/list/product/64/

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated