Hello. I am new to AVIC411 and I'm just got the D3 on sat. I have a Mazda CX-7 and I had the unit installed at BestBuy. The installer mentioned that he was having a hard time finding the spped wire, because everytime he searched CX-7 is was only talking about the model with the Moonroof. I have the Sport model with no moonroof and the regular stereo.The GPS antenna in located in the little window on the passenger side. My location is sometimes(mostly) behind and my Speed is very off. The signal stregnth seems to be good until it almost freezes and then it's behind. Any ideas and sorry if this