However, with speed equal, it gets more interesting. Boros is basically a version of Yusuke with less AP and LS, meaning that he'd get overwhelmed in his own bread and butter (frontal assaults). Boros' only hope here is to take Yusuke out immediately with
the heat from his energy-enhanced punches, but Yusuke is pretty smart and would deduce that his attacks are heat based. This would likely prompt him into defending with his aura, which gives sufficient heat resistance for Yusuke to be at least mostly unaffected. Even Boros' Collapsing Star Roaring Cannon won't seal the deal here since Yusuke can return the favor with a very strong reigan.
In the end, Yusuke would simply outlast and beat down Boros
when his Meteoric Burst form eventually runs out. Voting for the spirit detective.