Crutchfield carries the kits and adapter harness's. Wait a minute I think I have a set, let me go dig for them..
Dam, they were actually where I put them so I would not loose them which usually guarantees I'll never find them again LOL. OK
METRA part number 72-6512 for the speaker plugs
METRA part number 82-1010 for the speaker adapter plates for 97-98.
Schoche [sp?] is the other company that makes adapter.