Since that guitar has a floating trem, there is no way to quickly tune to different tunings. The only thing you could buy to make it quick is another guitar. :D

Buying a guitar with a fixed bridge will make it possible to tune to different tunings quicker, but, it's not good for the neck. When you tune standard, the guitar needs to be setup for standard (truss rod adjustment, intonation, etc....) and if a guitar is set-up for standard and you say, tune down a step, the tension of the strings will be different so the truss rod will need adjusting again. That's why your strings are higher off the fretboard when you tune back up to E, the neck had adjusted to the strings having less tension.