Hi, this discussion is ages old, but still not solved
I own an A4 mk2 and I really love the sound and the fun to dial in new sounds. As I do not have time and space to use my music hardware regularly, I try to find pugins that can a) replace my A4 and b) sound like a Novation Peak/Summit and can live on my notebook. It turns out that only a few software synths can match the features of both. Especially the lack of a good polyphonic overdrive/distortion in combination with a really good sounding, self oscillating filter is omnipresent. I just got Monark, Diva and Repro and will give them a try. They all sound great - but in a different way than A4/Peak. But tbh I did not yet take the time and dial in my own sounds to find out, whats possible.