Waze is a wonderful application for navigation, knowing where traffic, accidents, and knowing where cops are. My wife and I use it a lot on road trips. But, being cell phone based it is negligent to use when it is not mounted somewhere that allows you to keep your eyes on the road. To this end I installed a cell phone holder.
In terms of places to put a phone the (more or less) stock interior of a BRZ does not have a lot of good places to put a phone and see the screen while looking out the windshield.