How to add more horsepower to 2007 ford mustang. 4.0L v6?

[Jeff]

me and my buddies are working on my car. Custom paint job already and runs 368 hp out of a v6. As you can tell its not stock. We do not have a supercharger on it yet. Money is not a problem, but i do not want to go out and buy a gt. If i wanted a gt i would have bought one. We currently have it tuned customly, have racing headers. cold air intake. ignition kit. ford racing exhaust (willing to replace exhaust system) throttle body spacer. im not 100% sure but i think thats it. Just wanting to know if anybody has serios suggestions, guestimates on prices would be great too. Thx ahead of time