Im looking for help installing an aftermarket radio in my 05 Bonneville gxp which has northstar and a monsoon sound system. I would like to retain these features after installation.the only problem i have is which harness to get.so if anybody could help that would be awesome. Also im doing the install myself so any tricks or pointers are more than welcomed

Welcome to the forums.
I see that you have received help regarding the radio in the GXP Bonny Section.
https://www.gmforum.com/bonneville-g...le-gxp-310006/
Crutchfield can assist re the wiring requirements and any adapter plates etc.