Ayre MX-R upgrade costs?

The price is the difference between the retail prices (last MX-R retail price before it was discontinued now) and current retail for the Twenty (this increased recently) in your jurisdiction. 

The Twenty is a substantial improvement over the original MX-R.  No one can answer if it's worth it to you.  What are you looking for?

If I recall correctly, it it about $11K. From what I have heard the '20' upgrade is a significant improvement.
BTW, I own the MXR's, too, and I have a hard time believing that they can be made any better.
I would contact Ayre's Michael Wiedmair and get it from the horse's mouth. Though he can't say if it is 'worth' it, he can give you the details on what is upgraded and why it is done.
B

I would contact Ayre's Michael Wiedmair

I e-mailed Michael recently because I thought it odd my AX-5's volume would cranked down when I put it in standby mode (turns out the behavior is as designed). I found out that Michael is now doing sales and that customer service is now handled by Gary Mulder who worked at Ayre years ago.