The spec panel recalculates power and speed based on pre-defined lookup tables from real dyno tests of these parts. For example, adding a 70cc cylinder + 21mm carb + racing exhaust increases output from ~4.5 HP to ~12 HP.
Swap only the stock exhaust for a resonant expansion chamber. Dyno result: 4.5 HP, but torque begins earlier. No overheating warnings. Simson Tuning Werkstatt 3d Demo