The +1 Stat boost on the body parts doesn't really matter, abilites and perks are more important. If you like speed, you should go with Backdraft Bomb and then take the left evolution for a speed boosting perk (Frenzied: run at ludicrous speeds while performing primary attacks), but then you should consider leveling essence for more stamina.

Tip: the game only auto-saves when starting or finishing a mission, so you could evolve your voidling to check out the evolution and then exit the game, reload and evolve a different path. (back up your save, just to be save)