I had M80v2 for 11 years. With QS8v2, 600v2 and 150v2. The absolute BEST thing you can do for your ears-brain is move to v4. Read my upgrade post and reviews.
I now have M100, M5, M3, VP160, QS10 and EP800; all v4. They are nothing, absolutely nothing, like v2.
The M3v4 is better sounding than the M80v2. The M5 with a DSP-based sub like the 500 is a giant speaker killer!
v4 soundstage is holographic. Broad, way beyond the speaker boundaries, tall, deep (way deep) with layers along the depth. Images are very distinct with dead space in between. It is uncanny. The sound across all bands is truly impeccable. The mid-range and tweetage is spectacular.
The 160 is so far ahead of the 150v2. There is just no comparison.
The 800 is tight, transparent, musical and can pack a wallop in movies. It is nothing like the 600v2.
The QS10s showed me eveything that I was missing with the QS8s.
If you want to make the most of your cash, I suggest forgetting the M60s and going with the M5 on-wall. Remember the M5 has the HP driver. You may like a third M5 on-wall for the center if that works for you. If not, get the 160 and never look back.
Like me, you will kick yourself for not upgrading sooner.
P.S. You can trade in your old gear. And you will put up an image of Ian and Andrew and pay homage to them every time you listen to your system.