Re: JS1000 and adding springs??
On guitars with a fully floating trem, the other strings will always go flat when bending a string, it's just the nature of the beast. You can set the guitar up to dive only (using a piece of wood or a Tremol-no), but you will lose the ability to raise pitch with the trem. You could also try something like the Hipshot Tremsetter, which will reduce the amount the other strings go flat, but will give the trem a stiffer feel.
If you want add more springs, you'll need to remove the "Block Lock" (that flat piece held on with the two screws), and anchor the springs in the screw holes. It's not really necessary (I don't think you can pull up on the trem far enough to get the springs to pop out), but it is convenient to have when removing the trem for maintenance.