In both the TV series and the manga there are a lot of episodes resolved by Sunako and Kyohei kicking the asses of however many mooks need to be kicked, and it's awesome every time. Sunako's "self-powered" attack against Kyohei is probably the best of them all though.
Sunako jumping in to save Kyohei from being brutalized by a gang boss right after being taken hostage is pretty cool.
Interestingly in the anime the beatdown is done entirely in her chibi form making this double as a Crowning Moment of Funny.
In episode three Sunako sneaks into a host club that had kidnapped Kyohei, tore off her disguise to reveal a german uniform, whips out a chainsaw, saves Kyohei, and then begins going on a rampage as she destroys the entire building.