We're about to buy a 2010 Outback 2.5i Limited. We really want a back-up camera, but don't care much about the Navigation feature that it has to come with, nor the high price. The dealer has offered to install an after-market back-up camera with display in the rear-view mirror for a fraction of the Nav. option cost. Anyone have any experience with either? Should I be worried about any warranty "voids" if the mirror is replaced? Any features that you've found very useful that come along with the Navigation?