It's your car. If you like it, go for it! You don't need validation from us.
However, you did ask for opinions. I would definitely stay away from that stripe package. I agree with someone above that said our cars are pretty well designed without needing additional attention. I think the stripes you're considering make the car look more "racecar" and I just don't think our cars need that. I especially think these don't belong on a GXP. But, as someone else said, if they're removable, it should kill the value.
Good luck with your decision!
2009 SRM Premium and Sport Packages, Kooks 1 7/8" LTs w/ Cats, Corsa Cat-Back, Pat G Tune, CTS-V Brembos, RotoFab CAI, GXP Diffuser, Holden SS Steering Wheel, Holden Omega iQ Head Unit, VG Sharkfin, Homelink