Ignoring any Gohan was or was not SSJ2 against Dabra mentions, If SSJ2 Teen Gohan = Dabra >= Cell then I guess yes, that would settle it...Gohan was irrefutably stronger than Cell, at least according to official supplemental material.The Daizenshuu also mentions Dabura is equal to Cell’s battle power. Goku mentions Dabura is a lot stronger, but that seems like in response to his magic so Dabura’s magic > Dabura = Cell = teen Gohan. Teen Gohan is also stated to be far weaker than kid Gohan by Vegeta so that pretty much settles it. Kid Gohan > Teen Gohan = Dabura = Cell.
As for "how much" it's still up in the air.
Although Vegeta mentioned Gohan was "far, far better when he killed Cell."...he said so when Gohan was just standing around and not fighting. There's also a very high chance(if not fact) that Gohan wasn't at full power there:
Kaioshin wrote:“Un-unbelievable. Is this ‘Super Saiyan’ thing really this great?...Come to think of it, it was quite hard to stop Son Gohan from moving after he became a Super Saiyan…And even that might not have been his full power…”
The only other quote stating he's weaker as a Teen isKaioshin wrote:Kibito: “Huh…!? You can’t mean…Does this have anything to do with Son Gohan…?”
Kaioshin: “That’s right…His power is far beyond our imagination. If we took it and changed it into something even more unreal, he might be able to surpass Majin Boo…”
Kibito: “Wh-what!? That can’t be…”
Kaioshin: “You didn’t see how amazing those 3 Saiyans were, so you probably couldn’t imagine…”
So while Teen SSJ2 Gohan is clearly weaker than his kid self, I don't see anything that says it has to be by an enormous amount.Vegeta wrote:[Gohan]’s so pathetic…So much so that he was stronger as a brat…”







