Based on Niko414's experience with his GC with Comp Package, is say, you almost need the Comp Package on the Gran Coupe.
It's a tough decision for sure. However, keep in my you can mod the Gran Coupe with lower springs than the CP Springs and even add the CP sway bars later, or if you really want to be cool, you can get the Dinan Sway Bars which can be up to 79% stiffer than stock.
Good luck! I'd hate to be in your position.
