Fuel parts are very important to achieve "big power."
HKS Fuel Delivery Kit does not include injectors, fuel line parts, and a regulator. 
To use this kit, the injector must be a stock or select one from the HKS Top Feed Type Injectors of 550cc, 680cc, or 1000cc. The fuel line parts must be Aeroquip's and the regulator must be HKS Adjustable Regulator.

HKS Fuel Rail Upgrade kits are high-performance fuel delivery units that are designed to properly supply the additional fuel needed for high boost/performance applications. HKS Fuel Rail Upgrade kits are direct bolt-on replacements of factory fuel rails, and allow for larger top-feed injectors to be added. HKS Fuel Rails are machined out of aluminum and anodized HKS' signature purple for durability and visual appeal.