VIST plates are more than just a deflex plate. The plate you are all referring to is their 12 or 24 hole stinflex plate. Which is a deflex plate with holes drilled into the aluminum to allow for some natural but dampened flex... designed for super-g and downhill. The VIST plates that you find on Rossignol, Elan, Atomic, and Stockli are a totally different design. they are called the World Cup Race V10, V13, and V16. These are aluminum plates, each with a different height 10mm, 13mm, and 16mm. The hole pattern is similar to a fischer plate but the plate works off a different concept. It has three sliding layers of a flexible polymer and a flexible V joint in the center of the plate between the two thin sheets of aluminum (primarily there for mounting safety). The thicker the plate you mount - the stiffer it is... they are not designed to add height. If you only weight 150lbs and are using the plate on a slalom ski you dont need the 16mm adapter. Rather VIST will provide you with lifters to mount on top of the plate under you bindings to raise you to the height that you desire. They recommend the V13Alu for SL and the V16Alu for GS. The V10 is designed for younger athletes that cannot exceed 50mm of height, as well as lighter racers.
Personally i dont think that i would ever try to ski on the V16Alu because i just dont weigh enough. If youre looking for lift you can add risers to the top of the plate very easily. If you are just free skiing i would go with the V10 or the V13. If you decide on the V10 make sure that it is long enough to mount you binding/boot size to. Also the plate requires some very serious mounting so make sure your technician has done them before. They have several types of glue that are required in certain places or the plate will be on your ski totally wrong - the glue in part of the plate design, allowing the plate to slide more or less in certain areas of the ski. Whatever you do - DO NOT buy a stinflex, unless you are doing some serious racing in speed events.
Last season Elan marketed the 13mm plate with their SLX T. One person on this forum said that he cut the center out of his VIST plates on his Elan SLXT. This took out the joint and some of the aluminum in the plate - making it very much like a metal version of a Fischer plate. He claimed that this made the ski flex a lot more and made it very user friendly to ski on. I myself have never used a VIST but many of my friends who are racers love them. They are very popular on race stock skis because they allow for such a smooth ride. They do require a little extra work because of the aluminum in them - but you will find this is true with any lifter of substancial height.
And last but not least, the VIST website, where a good portion of the above information was taken from: www.vist.it
On the right side of the page there is a "Welcome" link which takes you to the english page, and from there you can navigate to products and chose your weapon. Each plate is described by how it is constructed and what it is used for as well as all of its stats i believe. If you do not wish to use the race plate on your stocklis - which would be foolish - but if you do not wish to use it; VIST also makes a huge line of carving plates, which are designed to allow for more flex and leverage - but less performance than the race plate. Those are all available at the site. I think that in total, VIST markets 20 or so different plates, from free riding to carving to GS, SL, SG, and DH. Their popular carving plates you will recognize as atomic race and carving plates that are on all atomic skis (i think anyways). VIST carries no binding allegiance, in order to appeal to racers who want to use a specific binding on their skis - even with their 'atomic like' plates.
Hope this helps - i know it is very long but i thought i would clear up some misinformation about the company.