PAC OS-2Bose GM
Metra Electronics Corp. GMOS-04 This one you can find at Best Buy for $99.99......
Both of these will retain door chime, Bose, and On-star....
if u call best buy ask them for the kit gmk-420 $19.99 it comes with the single din and a double din kit....for the harness ask them for the metra (its also known as axxis) gm-os4 $99.99 that keeps ur on-star....if u dont want to keep on-star its a scosche gms-lan2 I THINK!!....
Man i thought i had it good when i opened up my ps2 4 yrs ago when me and my wife was dateing now its all bout the kids my 4yr old is getting a wii luck-eeeeeeeeee!!!