The answer is debatable, but according to Frieza himself, Mecha Frieza was indeed stronger than his previous 100% form.
While this statement is made by Frieza, a character known for arrogance and potential self-deception, we need to analyze the context:
- Frieza's Claim: After being rebuilt by his father, King Cold, Frieza claims that he is now more powerful than ever before.
- Technological Augmentation: Frieza was severely injured after his battle with Super Saiyan Goku on Namek. The addition of cybernetic enhancements, according to Frieza, compensated for his lost organic parts and increased his power level.
- Potential Lies and Misdirection: Frieza is a known liar and manipulator. He may have exaggerated his power to intimidate his opponents, particularly the Z Fighters, before Goku's arrival. Admitting weakness would be out of character.
- In-Universe Ambiguity: The series never explicitly confirms or denies the truth of Frieza's statement through definitive power scaling or character dialogue from other reliable sources.
- Future Antagonists: Dragon Ball is notorious for power creep, and Frieza was easily defeated by Trunks, showing how much stronger characters would become.
However, considering that his father, King Cold, helped rebuild him and that King Cold himself was said to be stronger than Frieza, it is reasonable to believe King Cold had the technology to make Frieza stronger than before.
Therefore, while we cannot definitively prove it, based on Frieza's statement and the circumstances of his reconstruction, the intent was for Mecha Frieza to be stronger. However, the power level increase was likely insufficient to defeat Super Saiyan Goku or Trunks.
