VPI JMW-9 to JMW-9 SIGNATURE upgrade pros and cons

I am considering doing this upgrade at a cost of $620 all-inclusive. I would love to hear from anyone who has made this upgrade and their listening impressions, both good and bad and whether or not it was worth the $620. (I have set up my TT level, aligned the cart with a Mint LP protractor (highly recommended to me and now by me), tweaked my loading, set the VTA, Azimuth, set the tracking, and set the VTF. If you have a Zyx Airy 3 I would like to know if the Signature arm tames the EXCESS sibilance (as apposed to the natural). My TT is a Scoutmaster with the ring clamp and a Zyx Airy3 cartridge.
Thanks 'Goners for your help...
The Signature arm is, in my opinion, worth the money. You've already gotten the ring clamp, now you might as well hear what your table and cartridge can really do. I recommend using Mapleshade Nanomounts also, and since you will have to do your set-up again anyway, it would be a great time to do it. I am getting superb results with my Sig. Scout and Dynavector XX2MKII Cartridge. Try it, I think you'll like it!

Mapleshade is well known for their footers and spikes. They have made a very small version, the Nanomount, that goes between the cartridge and headshell, and another set that goes between the arm mounting flange and the plinth. The idea is to drain the vibration from the cartridge, headshell, and into the plinth. The Nanomounts are made with one small cone on one side, and two on the other side, and with the proper oreintation, they drain unwanted vibration away. They really do work, and are relatively cheap, at $95 a set.

Regards, and enjoy,
They are very easy to install. The little things come on a very thin transparent film. For cartridge/headshell, there are three attached to the film, and the configuration will fit many applications. In the event it doesn't, they provide a small tube of superglue, and you just arrange them on the film so they fit, and glue them to the film. For from arm mount to plinth, they come on a washer-like film, which you simply install on the mounting bolts.
Mapleshade's website www.mapleshade.com has all the details on them, should you care to look.