All of those fan-translated manga scans are terribly inaccurate and shouldn't be relied upon for anything. Better to look to
Herms' translations.
Sorry for replying to little individual bits of your posts, but I don't know how else to address each mistake.
Goku to Piccolo : He cant get stronger. Only weaker.
Goku to Vegeta : Build up strenght isnt solution. (transformation)
This is a slight mistranslation. In Japanese he doesn't say he'll get weaker, or even that he can't get stronger. What he says is something like, "It's tough in the Room of Spirit and Time, even if you're not doing anything. You can't get enough rest like that. [ ] Trying to force our bodies to get any tougher than they are now would only be asking for pain. And that ain't training."
Vegeta to Trunks : If Goku already mastered that form he doesnt go ASSJ or USSJ when he whants to power up to that level.
This one's also worded a little differently. In Japanese Vegeta says that if they've gotten used to Super Saiyan as if it were their regular state, then they'll be able to raise their power without straining themselves. This doesn't necessarily have anything to do with Grades II and III.
Goku to Gohan : Something should come up (transformation for Gohan). Limits are reached.
This one's closer to being right. Goku says something should turn up and that they've trained hard, going right up to their limits.
But what limits? The absolute, build in limits they can never surpass? I don't think so, personally. To me it sounds more like the limit of how strong they can get in the remaining time. See, there's such a thing as over-training (or "under-resting" if you want to look at it a different way), and the way Goku talks about not being able to rest properly in the Room of Spirit and Time, as well as how they'd do better resting and doing some final training outside of the Room before the Cell Game, leads me to believe that this is what was limiting them. Too much training and not enough rest becomes counter-productive.
Super Vegetto wrote:I'm proving you that Dbz logic is not same as Gt logic and that there is limit in dbz. Gohan is stated to got potentail unlocked to limit and he cant get stronger. You and other guy claim diffrent which is not the logic dbz is using.
Gohan after 100 years > Goku because Gokus potential powers cant get higher than Gohans but your logic is no limit which is also like base Goku gt after 10 years > ssj3 Goku Buu saga.
I feel like a broken record saying this in thread after thread, but this is why the word "potential" causes confusion. As far as I'm aware, in the Japanese version they never call what you're describing "potential". It's "dormant power"--power that a person already has inside them that is asleep. Gohan had his dormant power drawn out "beyond its limits", whatever that means. That tells us nothing about his absolute potential or supposed limits.