I have a 98 SE i have that stock Bose deck in there but a wanna put in a system.....wut am i going to do bout that big gap its gonna leave due to the size differential???

 

Most radios are sized as either DIN or Double Din I asume you have the Double Din. You can either get an aftermarket Double Din or just an Intalation kit that will make the single DIN fit

 

where can i get the Intalation kit from??? how much is it??and will it fit??

 

Pretty much where ever you buy the HU at should carry the instalation kit. It shoud not be more than $15

 

Nissan also sells the single DIN pocket that you can put in the console to fill the hole. Just use the pre-existing screws to mount it. Your head unit retailer should also have a pocket that fits in there. I got one w/my head unit package, but i personally liked the Nissan one better.