Michael, I had the M80, 150, QS8 and 600 - all v2. I upgraded to the 160 and 800 v4. Great upgrade. I should have done it earlier. In the third quarter of last year, I got the QS10, M3, M5 and M100 v4. The QS10 was a great step up from the QS8. An even greater step over the M80v2 was the M3 and a bigger step after that was the M5. The M5 is the highest value between the M3 and M100. You will love them. If you drive them with a good pre-amp and amp, you will not need a sub for music.
As for a receiver, you can read what I've recently found out about my Onk which I always thought was so awesome. Get very good electronics because they make a huge difference.
If Ian wanted to do us all a solid, he'd come up with a family of pre/pros that we could all embrace.
