Sets and bonus stats (based on how many pieces of the set you have equipped) are listed in Lancet's
Dragon Knight Saga FAQ/Guide. There is no way you can get the scorpion leggings (short of reloading a save before taking over the battle tower), but there are more sets as you progress in the game.
I used the full Mining Guild set (available in the Steam version and the North American Xbox release) from level 16 to 27, replacing everything when I could use the Bow of Orobas after getting to level 28. I checked out other sets in the game, but stuck with my collection of mostly random equipment (after the beginning of the game no random bow came close to the unique ones available).
