It'd probably be difficult to get it grittier because the Vic has a couple of extra quirks that would be hard to simulate, namely:
1) Distortion caused by capacity overload of the sound space when the volume is > 10. (Might even be an incorrect DC offset, dunno) You could do something with the 6581 filters maybe, but it would probably be too muffled.
2) The noise generator's 'resonance' overtone, you'd need a much wider resolution of samples than the 8 levels in this emulator. (Amusingly the arcade machine Gorf has a similar sounding noise channel)
Also it's a frame-based emulator so Viznut's Waves and digis are out.
