simplest way is to buy din size/double din size pocket from honda that replaces your current pocket under the radio. Price wise, i think they are bout 80-100.
Or if you want something more, then as Dray_Templar suggested, carputer, like I had in my car. I would put the carputer in the glovebox, and touch screen on under the radio. This way everything will integrate nicely.
hope this helps
cheers
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