You can contact Gene at...
http://www.gmpartshouse.com/
He can look up part numbers for you and his prices are good. I ordered some stuff from him to install an OEM hitch on my Enclave. He was nice and replied quickly.
Another option is...
http://www.gmpartsdirect.com/
If you don't know the part number(s) you need, you can email them but the are pretty slow on their replies. I haven't ordered from them, but it seems like a lot of people do.
http://www.gmpartshouse.com/
He can look up part numbers for you and his prices are good. I ordered some stuff from him to install an OEM hitch on my Enclave. He was nice and replied quickly.
Another option is...
http://www.gmpartsdirect.com/
If you don't know the part number(s) you need, you can email them but the are pretty slow on their replies. I haven't ordered from them, but it seems like a lot of people do.