Upgrading VPI Jr to VPI MK 3

Hi all,
I purchased a VPI Jr recently here on Audiogon and was wondering what to expect if I upgrade to the VPI MK 3.
Can anyone who has done this tell me their experiences with this upgrade. I love the separation around the instruments I get with the VPI Jr and Benz Micro Glider(M2 model), AQ PT-7 tonearm(Emerald interconnect) but the "presence" is not there. It's like the background instrumentation was turned down in volume while the lead singer is loud and clear(Bonnie Raitt/Van Morrison tunes). The folks at Rogue(I'm running the 99/88 combo) tell me this can be fixed with a new capacitor and tubes. Is there any other fix for this ? Different cartridge suggestions or different interconnects ? Thanks
If you want to hear what the Benz and Audioquest can do - which is a lot given their price - do the upgrade. I didn't do an "official" VPI upgrade (acrylic plinth/armboard and steel subchassis) but, instead, made my own plinth out of Corian, using the particleboard Jr. plinth as a template - total cost, about $10. I found all of my other parts - platter and bearing - used on Audiogon.

What I had found was that there is a "softness" to the sound on the stock Jr (Harry W. may disagree) from the platter and, even more, the plinth itself. The difference from changing the plinth was significant: opens up the whole sound bringing the "presence" you mentioned, as well as more detail, air, tighter bass etc. If you want more info on what I did, feel free to email me (mcpass@hotmail.com).

I would say, you should even do just the Corain plinth to start (it might take an hour or two - you need to cut it to size and drill 8 holes) and get the Mk3 platter later (the bearing is the same). You'd be amazed.
I started out with a VPI Jr., then upgraded to the mk3, and now I have gone to the mk4. DO the upgrade! Each upgrade pulled more music out of the grooves of every LP I put on the table. Music is much more dynamic now with greater low level detail and resolution. I also went from the Audioquest PT-6 tonearm to the VPI JMW Mememorial. This was a HUGE improvement! I never realized a tonearm change could possibly make that big of a difference. I too am using the Benz Glider cartridge. My advice is don't hesitate in doing the VPI upgrades.
Thanks folks for the responses. I'm going to change my pre-amp first since that is less expensive than the platter upgrade. I plan to then upgrade the platter to the MK III and build the Corian plinth. Audioquest also suggests an upgrade to an Anaconda or Amazon cable. That's probably also in the future. I never thought turntables would require so much tinkering but it also makes life interesting. Len