M* galaxies, with halo masses of about 10^12 Msun live in an interesting part of parameter space. Not only are they the "turnover" in the galaxy mass Schechter function, they also have the highest stellar mass (and baryon) fraction, very low bulge-to-disk ratios, and dominate the star formation of the epoch they live in. I will present the results of a sample of 18 cosmological M* galaxies, simulated using the state-of-the-art superbubble method for handling feedback from Type II supernovae. I will show that the key to obtaining a realistic stellar mass-to-halo-mass relation (SMHMR) is preventing the runaway growth of a massive bulge by driving outflows with large mass loadings. If this happens, SN feedback alone can no longer effectively drive outflows from the galaxy, and star formation becomes unregulated. This is a key piece of evidence that the peak of the SMHMR is due to the shut- down of SN regulation and the beginning of AGN regulation in more massive halos.