Talk about subjective mumbo jumbo!
Basics required to get more power are as follows:
1. More air and fuel in to the engine (CAI, better air filter, smoother air flow and less heat soaked into intake plumbing)
2. More efficient and complete combustion (better spark plugs and HT system, and better mixing of fuel/air)
3. Less restrictive and more efficient exhaust system (no not a loud one!)
That's all there is to it.
Now just to find someone who makes a kit or kits to achieve this......