Well, current model is called Sport SX and I'd treat it as equal even though there may be slight differences. SX can have high speed CPU (required for synthetic vision) but doesn't have to have it so you have to verify when buying. Older Sports can be either low resolution or high resolution but neither capable of SV without upgrade. They also have vertical commands "built in" whereas that's an option on SX.
even though it may sound confusing, it's easier than it sounds. There are four possible models -- Sport WS (low res), Sport HS (older model with high res screen), Sport SX (high res current model), and Sport SX SV (high res, syn vis, high speed CPU). Don't be turned off by older models - at right price they can be smartest purchase.