VPI owners--recommended upgrade

Normally, I don't start posts like this. I usually start a thread when I need advice (usually on particular music). However, Music Direct was recently offering a special on Black Diamond Racing clamps for VPI tables. The price was $149 and was labelled B-stock, however, it appears that it was not B-stock but just an overstock. Anyway, I decided I would try it. I really did not expect much--it's a clamp right--the VPI stock clamp works very well. Well, I was amazed. The immediate improvement was improved bass, both extended and better defined. But that wasn't all, the midrange layering was much better. Better imaging, better soundstage, really everything improved. This has probably been the most cost effective upgrade I have ever made to the analog front end of the system.

Now, that I have VPI owners attention, I do want to ask a question. I'm considering 2 other upgrades: Anyone with experience in the upgrade from the spring loaded legs on TNT models to the air bladder legs please comment on your findings and second, anyone with experience with the PLC conditioner to the SDS system. Thanks for you help--and if you haven't tried the BDR clamp--I think you'll be impressed.
I've been watching your post for a few days. I noticed that nobody responded. I'm going thru some of the same issues. I've got an old VPI and I wasnt' sure what to do first. Well, the first thing I've done is replace my very old cartrdige. That should be complete in about 2 weeks. After that, I'm going to rely on info from VPI. Email them. They'll tell you what to do first. If you want to see what they've told me, then email me privately. Please note, I'll not have email access from July 2 - July 10.

Can't comment on the air suspension vs springs issue with the TNT but one big improvement is to use a Bright Start TNT and the Air Mass TNT combination under the table. This is a major upgrade over the Deluxe Justarack I was using. Also, Weisfeld sells a dedicated TNT stand (not mentioned anywhere on the website but I saw it at the NYC HiFi show).

For the HW19 series tables, ditch the springs altogether and replaced them with BDR cones... this is definitely the way to go (you could always put the spring back).
The VPI power conditioner (SDS) does wonders for the TNT 3.5. Going from an older PLC to a newer PLC improved the sound, but going from a newer PLC to an SDS made the performance jump much higher still. The motor has two belts and a pulley assembly between it and a 21-pound platter. How could the SDS be that much better for sound than a recent PLC? I don't know, but it works really well: better tonal accuracy, imaging, dynamics, detail, and most of all, more engaging. A sense of focus and a feeling of correctness in the presentation increased when I moved to the SDS.
As for the pneumatic feet, a user I corresponded with a while back had made that upgrade and loved the improvement it wrought. On the other hand, when I asked Mike at VPI if going with the pneumatic feet or the TNT 5 platter and bearing (same price for each upgrade), he recommended getting the platter/bearing. Interesting.
I will be replacing my motor (SAMA) soon; mine is having trouble getting the platter to start when the speed is set correctly for 33.3 rpm. (I know there is a spindle replacement for the motor, but there are other issues with the motor as well.) I can report if a newer motor makes any difference if folks are interested. The new motors have a different cord and cord attachment arrangement. I am also told (VPI) that the build quality in general is better now, too.
(For reference, I use an SME V arm, Benz Micro H20 cart, on a granite slab on a Target TT5T stand; Music Metre Silver phono cable or Cardas PIB and Coincident CST I interconnects.)
Has anyone heard if the TNT Hot Rod is a good way to go?
Has anyone else heard that BDR clamps don't work with the TNT 5? I recall some BDR TNT clamps being sold on AG because they don't fit on the TNT 5 platter spindles correctly.