My wife's new Ford Escape Hybrid did not have an outside temperature sensor in it like her old Subaru did and she really missed it.  In doing a little research for an aftermarket one for her car that would look OEM versus cheap aftermarket, I ran across the Gentex auto-dimming mirror with the temperature and compass display built in to the upper right hand corner of the rearview mirror.  It is more than just the temperature sensor, but the auto dimming feature rocks.  I have the auto dimming mirror in my F150 and it works so much better than the manual kind because even if the person behind you has on their high beams, it lowers the reflected light so it's not annoying.  Doing more research on Gentex, I found that they make the auto-dimming mirrors for many of the auto makers, so we gave it a try.

When the mirror arrived, I called Ultimate Electronics and they said it would be about a $100 install, but they were backed up on appointments.  I called Car Toys and they said they could do it that day.  I went down and they wanted $300 to install it and said it was very complicated.  That was more than  the price of the mirror and I had read the directions - it's not that complicated, but I didn't have the time.  So we waited 2 weeks and paid Ultimate Electronics $84 to do the install, which took a pro about an hour to do - would have been a much longer job for me. 

This thing is awesome.  It looks factory, reads the outside temperature very accurately and the compass is close to what the GPS in her car shows.  The slight difference in direction is because we did not program what area of the country we live in to compensate for the magnetic flux lines - which vary across the US. Since she doesn't rely on the compass info from the mirror, we haven't changed it yet.

Bottom line - great product, reasonable price and very functional.  A++++++