The latest thing is appearantly replacing the modulator on the Commodore 64 boards in order to get rid of some of the mess found in the video circuit, the idea is that less components is less components to add noise to all of it (you can also omit components for composite video as well if only S-video is to be used with the computer). I found the schematics for a version of it created by Zero-X/OMS, this has been adapted to a physical PCB that should fit into the spot where the normal modulator usually goes on a longboard.

I experienced quite a bit of noise on the video signal after installing the board, this appears to be noise picked up on the motherboard itself from being in direct proximity with other signals, these are usually hidden by the fuzzyness added by the standard modulator. The same noise is the reason many want to install a Lumafix board in their computer, but removing it is probably better than covering it up - revision B of the Lumafix board has connection points for routing these signals directly to the modulator replacement instead, for that reason I recommend using these together (with Lumafix components left out).