Audio Systems: buying a new radio and nav system and XM, nav system, factory radio

Question
I have 2010Toyato avalon want to replace factory radio.I have no idea what will fit what . I thank you very much.

Answer
The very best database of size of openings for headends and speakers and interface wiring harnesses, etc. is that of crutchfield.com.

Suggest you go to "outfit my car" at this location:

http://www.crutchfield.com/app/car/carselector.aspx?lp=%2fapp%2fCar%2fMyCar.aspx

and plow through the question sequences which will lead you to the "stuff" that will go in your car.  If you need other items for the final fit and connection you can find all kinds of other devices at:

www.installer.com

Such as here:

http://www.installer.com/cars/by_car.php?carid=8526

as well as

www.oemautosound.com

Crutchfield, if you decide to purchase from them, will provide harness wiring adapters and instructions on installation.  They are very good.  

Hope this will lead you to outfitting your Avalon the way you want it.