I asked this before, Morgan. Apparently it's not worth the money. The process is tedious - remove grip, insert the sensicore, regrip.
When you say your hand is trembling, do you mean forearm or hands or entire arm? If it's your hands, I think it might be a grip pressure issue because I used to have them too. Loosen up or changing to a bigger grip might help.
Btw, I'm using S300 too.