Sota Cosmos Series III vs IV?

I have a Series III and, since it is having warranty repair work done, I have been offered an upgrade to the new Series IV, which just arrived in January. Anybody have experience yet of the sonic differences between these? (I use an OL Illustrious arm)
I had Kirk add two additional upgrades,"after" the series III upgrade,to my own Cosmos,some months back.He better isolated the motor,and added better damping to the sub-assembly(I believe he added small sorbothane discs to the holes in the sub-assembly).I must state that the table is simply AMAZING(I have a Graham 2.2 and a Transfiguration Temper-V).I really cannot claim how much is due to the additional updates,but Kirk,and Donna are very low keyed and not pushy(a great thing).If the new updates are affordable to you,go for it,IMO!Also,you must get a better umbilical p/c connection that goes from the pump/power supply to the table,and peel off the platter intermat.Both a "must"!!You can tell Kirk you spoke to Mark,at Sir Speedy about this.
The amount of info retrieval from my own Cosmos amazes me,at the moment,as this design is absolutely fabulous,and a very good investment,when one considers how much some competitors charge,for similar performance.

BTW....could you tell me exactly what the claimed differences are,in the update from series III to series IV.When I went from series III to the additional updates,this new work was done as a kind of favor,to me,so there may be some additional updates added as of now.
One thing for sure,Kirk is now doing some fabulous "tight toleranced" work on these classic designs.My own table is GORGEOUS in the high gloss black fountainhead.I have a friend who has the RED platter top plate,also in black fountainhead.STUNNING!!
Best of luck.
The series four has a number of differences from the series three, and is ultimately a much more versitile turntable.

One of the drawbacks for me with the series III was the lack of adjustability of the VTA on my TriPlanar arm. Kirk has cleared up this issue by adding distance between the top of the armboard and the top of the platter. The increase is about 3/16" which is a huge increase. This was done by increasing the length of the spindle in which the bearing sits. There are several parts that were completely re-machined.

There were a few other things changed, which are probably what speedy mentioned above. Kirk said there was something done to isolate the motor better.

Kirk or Donna can give more detail in regard to what is done, but I can attest to the audibility of the changes.

I got the very first Mk IV made (kinda gloating) and I think it is worth the cost, and the 14 month wait. There won't be that kind of wait, so in that sense you are better off than I. The improved control, dynamics, and speed is easy to hear.