US models come standard, and are only available with 3AP: Gray Band front windscreen (known as the Grad tint windscreen for the UK). The HUD replaces the Gray band windscreen because it cannot be combined. I believe that ordering HUD brings it back to the standard windscreen.

I'm not aware of any addtional windshield options for the X5. 358 is listed as "Infrared Reflecting glass". I did a search of thru the various model configurators. The 7-series has 358 (Kilmakomfort- Frontscheibe) available.

I suggest using the vent function of the panorama moonroof (if equipped) whenever possible to keep the interior from becoming an oven. There's also parked car ventilation settings in iDrive I believe.