Von Schweikert VR4 Upgrade to VR5/7

Anyone have an upgrade for this from VR4 to VR5/7. How good it sound and worth for it. Please give your opinon, thanks
I'm also interested in this since I am the original owner of a pair of VR4s since ca. 1995 (I ought to bake them a cake for their 10th birthday).

Any advice on doing the VR5/7 upgrade versus switching them for the VR4 jrs?
Just went to a Demo and discussion presented by Albert Von Schweikert in San Francisco. He had with him the VR4 Seniors...Amazing. I'd go with the Seniors vs the Juniors any day.

I've got the VR4 Gen II and it seems like upgrade would come pretty close to the Senior's performance from the looks of the drivers and configuration.

Give them a listen,