you can either cut the cross member to fit a type-r/replica header, or just let it vibrate the hell out of the car and it will eventualy notch itself into the crossmember (did it but don't recomend it, lol)
only thing is if you're DA is slamed that header won't last very long,and could mess up your oil pan, it's already a close fit, the only thing you have to do is take out the middle crossmember that goes from the front cross member to the subframe (Gsr's don't have them anyways so it's not going to hurt anything) Ive had mine on for about 9 months, with no problem, mated to an aftermarket cat and greddy sp2 exahust. I even passed CA smog with the setup.
setup is B18B with R replica. It won't get in the way of the AC or anything else and you get some nice power (butt Dyno) in the midrange and near the top but don't expect much if you're running it on a stock ls.
