FYI, if you want a nice factory looking upgrade, check out the rear view mirror upgrades w/temp sensor (goes through the firewall via an existing grommet and sensor mounts in front bumper cover), compass, auto-dim, map lights and Homelink (wireless for garage door opener)... For all these features (50-GENK60), you can find them for $350 or less shipped -- Circuit City will install for $60...

Gentex HomeLink® Compass/Temperature Auto-Dimming Mirror with Map Lights 50-GENK60

There are other brands if you don't want all those features -- but it's nice to integrate the map lights as with the factory mirror to the automatic lights...