Comparison of DSEP tracks using built-in physics modules and MESA modules for opacities, EOS, MLT, and the atmospheric boundary condition. These tracks are for a 1.0  M _☉ star with initial X = 0.70 and Z = 0.02 evolved from the fully convective PMS to the onset of the He core flash. Only the H-R diagram shows the full evolutionary track. The T _c panels omit the PMS in order to highlight the regions where the differences are most pronounced; the lifetime panel focuses on the end of the main sequence and red giant phase for the same reason.