Let me clarify the intake, short ram means the air filter is located in the engine compartment. I hope that water or mud would not get to it otherwise, you'd better be wearing scuba gear.
As for headers both the GV and XL-7 have factory headers. I don't see much gain from designing from scratch. Your money is best spent elsewhere.
The guys on the Aerio board want me to design a header also, useless for the 1 hp you gain.
Thanks,
Philip