I have two ideas...
-He'd look like the same,except he'd be in the bright green color of his perfect form.
-He'd look like what he was looking like while transforming after absorbing Eighteen. (when Trunks
was trying to beat him up before completing his trasformation)
I think Seventeen wouldn't insist on fighting him after that and they'd escape.Maybe Kuririn would
have pressed the button,so Cell's plan would've failed.If Kuririn had still felt sorry for them,i guess it
wouldn't have been different from there on.