The state variable representation of the Virus filters probably have a feedback block in them already. I would guess that the drive would be some sort of nonlinear wave shaping block that models the nonlinear response of semiconductor (or vacuum tube) current-voltage relationships outside of a particular range of inputs.
I don't think my TI2 will ever come close to replacing my Eurorack modular and vice versa. There are just way too many patch points and routs possible on the modular. Also I can add features at will by acquiring more modules. The modular is not going to do high polyphony or chords any time soon (though with my Morphing Terrarium it does wave table scanning). My opinion is sort of in the other direction; that is I think an analog modular and a TI2 complement each other quite nicely. This is one of the reasons why I got the TI2.
I also am a fan of ACE. It sounds great, is priced quite well, and for me is fun to program. DCAM Synth Squad does a pretty nice job at analog emulation as well.