I installed a Brass Big Block from Floyd Upgrades (.com), who I think have re-branded to FU Tone or something. Amazing difference, really brought out a big (but not too big) boost to my low end. Made the guitar sound a lot more "whole" and noticed the axe had a bit more sustain too. Went on a bit further after that and got one of the little brass brackets with an allen bolt in it to turn the FR into more of a hard-tail (also great little thing to have on the guitar to make re-stringing easier), which even further increased resonance, sustain and tonal detail.
If I bought any more FR equipped guitars in the future, I will replace the block the moment I get my hands on it with a brass block and trem-stopping bracket. Just such a great difference.
Ah here it is:
http://www.fu-tone.com/catalog/Also, I have dealt with Adam personally a couple of times and he really knows his stuff. Really helpful, easy to get along with, and he sent me a T-Shirt for a YouTube review I did of his products a few years back.
Not sure how the prices compare now that there are a lot more companies on the market, but out of loyalty I will always use Adam's stuff at FU.