I don't think the GT cams are radical enough to give you the lope you are looking for. Aftermarket cams would probably be a better choice. You will need a new set of springs (perhaps retainers as well) because the steeper cam ramp and higher lift where the stock Cobra springs won't cut it (I once ruined an brand new set of W2 race heads from floating the valves from an extended 7500 rpm run). It won't be cheap and you'll need to degree all 4 cams. I think your looking at between 2 and 3 bills when all said and done.
keep this in mind. A radical cam will make the engine stumble more at low end, hurt gas mileage and may make passing emissions more challenging. That is a big price to pay for a lumpy idle which I agree does sound great. Not many guys swap out their cams on these cars because they don't buy you much anyway. The stock cams are actually pretty good right from the factory.
Personally I think a twin screw would be a better place to spend your dough but that's me.
Yeah skip the GT cams, I've heard them live and not at all impressed.
If you absolutely have to do it get a set of custom grinds from your favorite builder. It's going to cost though!!