speedview for android maybe iphone, its alright, it has a double on the windshield because the windshield isn't made for it, but it works, just a little lagged like you'd expect with the GPS

Yes, you can use the HUD with a Non-HUD windshield as stated. The HUD windshield just has a special coating in it in that area to stop the image from ghosting. Without it, the light actually reflects off both the inner and outer plane of the windshield, giving you what looks like a double or ghosted image. To some, this is hardly noticeable, or atleast acceptable given the cost of the replacement windshield. Many guys with Regals will swap the GP hud into their cars without the HUD windshield and have no real complaints.