Goku in the manga doesn't hit a power level of 8000. The power escalation in the story doesn't go that high for him. There are various factors and story arcs that determine his power growth, but 8000 isn't one of them.
One pairing that pops up is Goku and Chi - Chi. Their relationship as husband and wife can be explored further in fanfiction, especially in scenarios where Goku's Saiyan nature clashes with his family responsibilities. Additionally, Trunks and Future Mai is a pairing that has some popularity. Their relationship in the future timeline and how they support each other can be the focus of some great stories.
No. In the official 'Dragon Ball' story, Vegeta is Trunks' father. Fanfiction might play with the idea for creative or alternate universe purposes, but it goes against the original lore.
Obviously, Goku is one of the main characters. Since it's about him being born with a high power level. And his parents might also be important characters as they would be related to his birth and the discovery of his high power level. Maybe there are also some Saiyan elders or trainers who play a role in his life as they would be interested in his power.
Goku's power is measured in different forms and levels in his universe. When it comes to Legendary Pokemon, some of them have the ability to control elements like time and space. In a fanfic, Goku in his Super Saiyan Blue form might be able to match the power of a Legendary Pokemon like Palkia, which has power over space. But it also depends on the situation. If Goku is in an environment where his Ki attacks are less effective, like in a dimension where psychic powers are dominant, he might have a harder time against a Legendary Pokemon like Lugia. Overall, it's a complex comparison as their powers are quite different in nature.
In the context of this fanfiction, his high - born power level would have a huge impact on his early days. He may grow up faster in terms of physical strength and combat skills. Since he's born with such power, he might not face the same challenges as other Saiyans in developing basic abilities. However, this could also lead to overconfidence. And perhaps he has to deal with the burden of high expectations from his community at a very young age. He might be constantly pushed to test his limits, which could be both a good and a bad thing for his development.
Well, Goku's power level progression could be different in that he might be more in control of it. Since the head injury had some impact on his psyche, without it, he could have a more calculated approach to increasing his power. He might not rely as much on the Kaioken technique, which was developed in part due to his need to overcome limitations caused by his injury - affected development. Instead, he could focus more on pure Saiyan power - up methods like the Great Ape transformation and evolving it further.
In fanfiction, one interesting aspect could be their different power levels. Goku is known for his Saiyan strength and his ability to reach new forms like Super Saiyan. Trunks, on the other hand, has his own unique fighting style. Fanfiction might explore how they train together, with Goku perhaps teaching Trunks some of his more advanced techniques. This could lead to Trunks achieving new levels of power as well.
Fanfiction authors often like to experiment with different 'what - if' scenarios. Making Goku Trunks' father could be a way to explore how the story would unfold differently. Maybe they want to see how Goku's influence would shape Trunks' personality in a way that's different from how Vegeta does. It could also be a way to merge different story arcs or character traits that don't usually interact in the original series. For example, combining Goku's pure - hearted nature with Trunks' more serious and future - focused attitude. This can lead to a whole new set of adventures and character developments that are not possible in the official story.
Their team - up also benefits from their shared Saiyan heritage. They can understand each other's drive for power and the importance of protecting their loved ones. This common ground allows them to communicate effectively during battles. For instance, they might use a combination of Goku's instant transmission and Trunks' swordsmanship to surprise their enemies.