I finally received my m7 Stubby antenna...LOVE IT!!! Looks far better than stock. However, Im just not sure how well the antenna will work with NAV. In any event, I plan to keep the stock antenna in glove, incase of road rage.

 

Nice! I recently got the Alta 4" antenna and had the same concerns. Everything's been fine, even confirmed it with them on the phone. They said the incompatibility was due to fitment before, not reception loss.