I had a nice conversation with D3's Paul Crawford today, and learned a bit about the 2014 Quest and two new Rockerblocks. The 2014 Quest is a tweaked version of the 2013 ski--not just a new top sheet. It's not a radical departure in any way, but there's been some fine tuning to the layup and rocker. The new layup gives the ski a bit more torsional stiffness, and the flat spot has been moved back slightly.
The range of three Rockerblocks (four if you include their flat block) is indeed intended to provide another tool for ski tuning. The R30 comes stock on the new Quest. In addition, there will shortly be an R45 and an R60 available, each adding more rocker to the tail of a ski. They will be selling them individually, and in a package of three at a discounted price to buying them individually. All of them fit all D3 skis going way back. This means they can be used on the X5, RC, Z, Rose, etc.
Bolting any of these Rockerblocks to any of these skis will add more rocker to the tail of that ski. The more rocker you have in the tail, the easier the ski will turn and the more angle you will have at the exit from the ball. The tradeoff is speed and effort. In fact the tail of the Quest is quite flat until the R30 is bolted to it. Not surprisingly, Paul has played around with all these Rockerblocks and this is his current read on them. He found the R60 made the Quest turn like crazy up through -28 and -32, but at shorter lines than that, the ski turned too aggressively for his taste, and reducing the rocker became a better setup.
On the other hand, the R60 is a wonderful tool for making any D3 ski turn easier for less experienced and less aggressive skiers. "Novices will love how easily the ski turns with an R60 on it," reported Paul, "and the extra angle helps novices as well." For more advanced skiers, if you find yourself having to force the tail of your ski around turns, which can cause wheelies etc., adding a little more rocker to the tail can both bring the tip down and make turning easier.
There you have it. The 2014 ski is an improved design, and variable tail rocker allows for that much more personalization of your favorite D3 ski.
... Your ski should be your dance partner, not a wrestling opponent