Is it better to get an aftermarket nav on the TL or factory. I am really wanted to put one in my car but I need to best advice on this one.

 

What kind of aftermarket nav are you thinking? I currently have the factory nav, but it's nothing great. Upgrading the maps have to be done through a disc, which cost around $100, and the latest one is the last update they'll be doing for the 3G TL.

If I had no nav system, I'd try to upgrade to a double din with GPS. Even if you don't have free map updates, I'm sure that there's better functionality that comes with those, such as aux link and the like. Just my .02...