can someone help me out

hi i have a 91' astro and want to upgrade the factory speakers. i saw some that i liked but im not sure if theyll fit. so can someone tell me if these speakers will fit in the dash and rear doors.

http://www.futureshop.ca/catalog/proddetail.asp?sku_id=0665000FS10044294&catid=11042&atab=3&logon=&langid=EN

Thanks :)

look here http://www.crutchfield.com/S-idmFQtjCXRj/cgi-bin/autoinfo/autoinfo.asp
i dont know how reliable the website is but it might help