>>279863432>>279863711 (OP)>from Semi-Perfect Cell level to being Super Saiyan 2? How is him regenerating his perfect from related to the Zenkai. His cells remembering the perfect form and gaining the Zenkai are two separate events.
>You seem to be underestimating how powerfull Cell's Zenkai's are.They are powerful but you seem to be overestimating them. Cell has a SS Grade 4 equivalent in his perfect form. He is weaker than a hypothetical enraged full power SS1 Gohan. He gets a Zenkai + unlocks a SS2 equivalent and is still below a hypothetical enraged full power SS1 Gohan. This Gohan in a hypothetical SS3 would not be able to defeat Fat Buu. Buu Arc Goku was stronger than Gohan at max power and was unsure if he could beat one of the weaker Buus. If Cell got a Zenkai and unlocked his SS3 equivalent he would be under Fat Buu concretely.
If Cell goes up against Super Buu it's over. SS1 Gotenks is an equivalent in strength to SS3 Goku if not stronger. Gotenks proceeds to get SS3 and Super Buu was still ahead in strength.
Cell would have a very tough time against Super Buu. He might be dumb enough to let him gain a single Zenkai but no more.
Against Buuhan Cell has zero chance. Buuhan has Piccolo's memories and intelligence. Buuhan wouldn't let Cell gain a single Zenkai.
As for the OP question, Buu Arc SS3 Goku would beat a SS3 equivalent Cell.