Saw the M3 mule at the M Studio on the 4th during the M5 launch event. Don't remember seeing the HUD, but the engineers specifically talked about working with the base cars core components/electronics. Now that the base 3 has HUD, they have the ability to add and use on the M3. I would Beverly shocked if it didn't have a similar HUD to the M5.
Current: '13 E92 M3 Euro Delivery
Wife's: E36 M3
Gone: E86 M Coupe; E30 M3, E39 M5