I can only find specs for that Pioneer that state the output is at 1% THD, so I would say yes, it is under powered. You are now hearing much cleaner power through your speakers.

Only one way to know for sure if you will hear a difference from your $200 speakers to the M80s(top of the line comparison to top of the line) Buy a set and compare them, if you don't like or find very little difference you can ship them back.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70