I have been looking on the net but really can't find anything. I have 2k GSR I was thinking, would it be worth the time and money to swap the c1 head with the c5 head?

No, then you'd need a new intake manifold. Just get some cams and a port and polish.

Cool some one else from GA hehe. Yea the c5 head is not that much better and with a port and polish job and some cams you will be just as good.

Thanks guys