You can modify it if you feel so bold and have an input. Several have done it for the older style (including myself)... not sure how on the newer models, but It can be done, if one were so inclined.

http://www.grandprixforums.net/auxil...dio-61160.html
^ What I followed to do it on my 99 GTP. Radio is different but the setup is most likely the same.

___________________________

If this is all too much tho, just buy a replacement/aftermarket radio with an input. A factory replacement would have to be programmed to your car anyways, aftermarket is usually a ton easier.