Here I am using Zebra2 to illustrate a point about the slope of the filter modifiers.
In the first 18 seconds, listen for the subtle but noticable change. I am NOT working the cutoff filter here. I have used Zebra's v-slope filter in 8sx mode option. The change you hear to the sound is simple changing the curve of the attack slope. Notice the effect it has on the bite? I am moving it very slowly to make the point. At 18 seconds I slide it back all the way to the left, and you can hear it return to how it is when the clip beings... then I reach for one of the cutoff filters at about 23 seconds in (this patch actually has 2 VCF filters on it) and open it up for the last few seconds of the clip.
http://www.mediafire.com/?oqv1aei57g2fzn3
Hope that gives an example of what I mean by the slope of the filter envelope being the "sink or swim" element of a pluck sound. I am not sure what options the Virus has here, but the envelopes of all the factory patches sound very linear to me... so different, non-linear slope types might be sort of a buried option on the Virus?
By the way, I've been talking alot about Dune here. Zebra2 is also a freaking monster synth that I dare say is probably not only capable of everything the Virus can do, but due to some of special oscilators, someone really skilled in modular synthesis can probably create a whole category of acoustic sounds with it that would be harder or impossible on the Virus, simply because the Virus is not modular at all.