jocifer1,
I moved your post to the Electronics section forum.
In response to your question. To use an aftermarket DIN or Double DIN radio in the Fit, You and other North American buyers will need the Dash fascia from a Asian or Mexican/Brazil spec car.
From earlier post it will be about $300 for the panel but it opens a lot of options for what you can use in the car like Double DIN navigation systems. You might have to wait a little while until this piece becomes widely available.