I have been using - happily - a pair of VR4's Gen III for the past few years and just went for the upgrade that Albert offers for those at $2500.
He described the result as being as close as one can get to VR5, with improved efficiency, openness, clarity and detail. Only the outside stays the same. On the inside, everything is new, including cabinet liners, crossovers and drivers.
My speakers just came back after a very few weeks of waiting and I could listen to them over the past weekend. Everything that Albert described was there, and then some. I drove them off a First Sound MkIII preamp with Rogue Audio M180' upgraded monoblocks in triode mode, using various fronts and running all types of music, from voice and solo instruments to full symphonic orchestra, from jazz to classical.
Overall, the net effect was stunning. It felt as if my original speakers were working through a heavy screen. The closest comparison I can think of - in terms of the new clarity and detail - is the sound produced by Avantgarde Acoustic Duo's in a 75k system. I am a most satisfied customer and at least for the next few years, I will feel no need to go after a pair of VR5's.
To all of you still hesitant, if you are willing to pay for good sound only and forgo the looks and cost of expensive cabinets, Albert's mod of the VR4's GenIII will certainly be an extraordinarily satisfying experience. If anything, it will make you feel as if you are listening to a whole new and much better system altogether.