Ok I'm looking at getting the following parts for my new 370Z sport coupe. All parts will be from Stillen. Any advice on where to buy at the cheapest rate would be greatly appreciated.

Stillen HFC priced at $499.00
Stillen CAI priced at $549.00
Stillen Exhaust priced at $1197.00
Stillen Headers priced at $567.00

According to the Stillen website with all these mods added I'm looking at an extra 60HP. Any advice or suggestions would be appreciated.