The anime says he actually reached Buu Arc Ultimate Gohan level

​@@Alllex Oh right, I missed that Gohan even said he reached Gohan's top power, which is Ultimate Gohan from Buu arc. It's just that Vegeta was able to defeat Ginyu in his body, who accessed more of Tagoma's power. Vegeta in base was equal to Cabba, and that Cabba in Legends was weaker than New Cell in Perfect form even with SS1. It took a combination of SS1 Cabba, SS2 Shallot and post-Cell SS2 Gohan to beat Super Perfect New Cell. But those 3 couldn't beat a different newly revived Fat Buu. Though I guess it's possible that they were both trained to reach Buu arc level of power before confronting Cell. It was imply that Goku didn't retained the SSG boost after BoG, hence why he has trouble with TOP foes like the Trio of Danger (except Belgamo) when they're not even surpassed DBZ level of opponents, hence even Cabba in base alone isn't really that strong. I know Legends is non-canon, but I believe that anything official is canon and the game has Shueisha's involvement like almost all of DB official product.