Not sure the heat pump upgrade is all that great for people driving mostly in warmer climates, such as southern CA, given the noise the pump produces, complexity, cost and reliability; compared to the simple resistive heat coil. The heat pump in 2021 M3’s appears to generate noticeably higher levels of noise; buzzing, grinding, humming etc. compared to the resistive hvac heating. The heat pump upgrade seems to benefit people in cold climates; not sure it’s a better for people driving mostly in warm climates?