You might start by viewing the comparison chart on our website, here.
The Elite and Pro are similar in fit. However, the Elite is made from a knit material that is heavier and not as compressive, and it has the traditional zipper with a lanyard versus the autolocking zipper.
The Pro is made from a stretch-woven material, making it lighter weight and more compressive in the legs, as well as an auto-lock zipper which eliminates the need for a lanyard.
The Viper X adds on modifications to the arm holes making the suit more comfortable and thermobonded taping on the inside that will add incredible support to the core. It's important to note that the taping makes the Viper X the least flexible suit. It's common for athletes to go up a size in this model.