Your list as of yet:

Cold Air Intakes +8HP
www.needswings.com
www.tvtdesign.com

Cat-Back +5 HP
www.borla.com
www.magnaflow.com

ECU Tune (+12-+23HP)
www.inmotion.com
www.tvtdesign.com (call first)

Injectors (allows for more HP)
www.tvtdesign.com

Ignition Wires (+5HP)
www.letmotorsports.com
www.tvtdesign.com

NGK Spark Plugs (better idle, possible HP increase)
www.letmotorsports.com
www.amazon.com
www.tvtdesign.com

Underdrive Pulleys (+6HP)
www.evosport.com
www.letmotorsports.com

Modified Thermostat (cooler running, possible HP increase)
www.tvtdesign.com

Modified Airbox/Hi Flow Filters
www.tvtdesign.com

Air Pump and EGR block off plates (cooler intake charge)
www.tvtdesign.com

Camshafts
www.schrick.com
www.tvtdesign.com (Much cheaper if a group order)
I believe Turner Motorsports carries them as well


I think that about covers it as of right now. I'm sure I'm forgetting something, so feel free to add it in there.