The quick quick is that the Senate platform is based off the high end ski shape (Vapor) and then surface area is added by widening the ski 0.2". The extra surface area gives the ski more float/support while retaining the majority of the high end characteristics of the Vapor. The Senate line of skis are extremely fun to ride and are capable of skiing very short rope in the course at 34mph and below. Radar offers different "builds" to accommodate a wide range of skiers wanting the ski. The idea here is that the different construction materials of the different builds offer a performance enhancement much like would be found in different mountain bike builds for the same frame. The higher end materials that are added, the more responsive the ski becomes, while at the same time shedding weight, making the ski more efficient, reducing physical fatigue for the skier (sorry for the run on sentence). More is not always the better choice depending on typical conditions the ski will be used in. The Alloy (base model) is a great skiing ski that will perform extremely well in all conditions and will manage skiing through chop and rollers especially well due to its more robust construction. It sort of pained me to call the Alloy the "base" model so I'd like to clarify this by saying that Radar's "base" model would be like buying a base model BMW. It still is a driving machine just with slightly less upside. Then there is the Graphite line which offers an upgrade in materials that is noticeable as soon as you pick the ski up to go to the boat (lighter) and its benefits are felt at the finish of the first turn with faster acceleration off the buoy and less fatigue on the body. This will be the theme just heightened as we continue up to the Senate Lithium which has the same construction as a lot of the high end skis offered today from Radar's competitors. Shedding even more weight and adding a higher level of acceleration and responsiveness out of the turns. Finally we arrive at the flagship Senate, the Senate Pro, which is built with Radars highest level of construction (Vapor Pro Build) while being held to the strictest of tolerances during the build phase. Think 0.2" wider version of the industry leading high end ski. This is a ski capable of setting the world record at 34mph or be used to absolutely slay a glass calm open body of water. In most cases, I recommend going with the highest build level you can afford. I would also recommend buying the most recent year of the ski possible. The Senate line evolves with the newest Vapor shapes, thus the newer the ski, the more evolved the shape is. This provides you with the best performing, most predictable, best skiing Senate possible. Hope this helps clarify the Senate line of skis.