First question is what is the upgrade you are hoping to achieve? Is it just to make the new tv upgrade and make it all fit or are you trying to improve something with in the audio? More details will help to give suggestions. I have m3 and m2 but have not heard the m5hp, yet. Were you thinking m5hp on walls or going fullsize?

M60ti Hafler9505 & JFET Pre,Axiom Transformer. M3 Marantz PM7200 Dual 606 Denon 2700 M2 Yammy RX595