http://www.crutchfield.com/S-e5h9SXMQr7u/App/Product/Item/Main.aspx?i=130P3000IB
vs
http://www.crutchfield.com/App/Product/Item/Main.aspx?i=158GT320&tp=5684&tab=detailed_info
main concerns are being able to see whats on the screen at all time (i.e. no glare). probably using auxiliary...