ok so i plan on ordering my new head unit today, but needed some questions answered first. http://www.crutchfield.com/S-40RNKItDNml/p_1301200MP/Pioneer-DEH-1200MP.html?tp=5684 this is the head unit im buying. right now all i have is a am/fm stock stereo and theres a pocket below it to store things and such. do i still need to purchase this: http://www.crutchfield.com/p_081TOYPOC/Toyota-Nissan-Dash-Pocket.html?tp=3121 in order to make it fit or does it just slide in and can use the "stock" pocket i guess. thanks for the help