It's all personal preference between the 2 kits and many will choose the Stillen over the GTM because of the CARB legality. I've had both kits and the Stillen did gave me quite a bit of headaches before but I truly believe they already figured everything out by now.

GTM is a whole different animal in my eyes, my car has been treating me the way it was intended to do and no issues ever since installation and tuned by GTM. I would say if CARB is something you don't have to worry about you should def consider the GTM kit.

That's all I should say and there are multiple threads over at the370Z forum on this same topic. Should go roam over there to check it out