Make your own as you can't get a gsr kit for love or money... I've tried a few out there and to be honest for the money they want and what you gain I would make your own, I have its lasted nearly 5k so.far and I haven't looked back..... Great dump sound.from turbo, good acceleration and I paid a fraction off the price also dyno shows a 8-10bhp improvement over stock which I believe is great considering I made it completely....