Abstract: For the first time, we conduct controlled experiments on turbulent Milky Way progenitor discs with gas fractions ranging from 0% to 100%. These are designed to match the latest ALMA and JWST disc observations in order to understand their short-term and long-term evolution over billions of years. The star formation coupling, efficiency and feedback prescriptions are calibrated against 12,000 3 simulations of kpc-scale turbulence. Turbulent discs really are different. Even with their highly energetic dynamics, they are able to form spiral arms, bars and bulges, but with important distinctions from quiescent discs. Interestingly, gas bars can form and thick stellar discs can arise from the fluctuating disc potential, as we discuss. We will cover special topics: do bars aid or suppress star formation, do turbulent discs aid or suppress the central black hole’s activity, and so forth.