The Schumacher won't have the flow. Looking at going the custom route. The hookers are fenderwell headers. Not cutting my car apart after I just got done patching it there.
Bulls**t. Do you have a flow bench to prove it? Pipes only flow as much as their narrowest point, which happens to be the same spot on all of them; the flange, and the 90* bend there-after.
PS: What the hell do you need 600HP on the street for? Where are you going to responsibly let that loose? C'mon man, be realistic.