I have a shapeshifter (among other module). I love it. Sure, the A4 filter works and sounds good, but you’d be missing out on a lot of other functionality. Maybe think about a full voice system like the intellijel atlantis?

Not sure what you mean about the iPad thing though. I don’t use my iPad to control my modular but in theory I guess I could via midi. I DO use my iPad to control my A4 though.