zulustypes

Was wondering if anyone has done this? I have been contemplating on doing this to my car.. i am sitting at 303 whp 270tq SAE on a dyno jet with the Greddy T517Z turbo, but runing out of efficiency on my turbo... I gain squezze a few more HP, but would rather do it with a bigger turbo.. I like all my setup, so would like to keep it if possible... just wondering if anyone had ideas as far as maybe another turbo that will bolt up to it, or maybe another brand turbo and just get the manifold to mate to my exhaust? any ideas ?
thanks