Great chapter, but it also convinced me that having Kaoru like Haruhi was completely unnecessary. If he doesn't like her enough to get a LITTLE upset if he saw his own brother kiss her, or hearing her go on about how she's worried about Tamaki, then he doesn't like her all that much. In which case, it was unnecessary. The author just wanted the twins to have a fight, and while I agree that it would be difficult thinking up a different reason for them to argue, I feel like having them fight over Haruhi was pointless and makes Haruhi a bit Mary Sue-ish in that all the guys like her.
Still, I loved how Hikaru and Kaoru made up, and the overall chapter despite Kaoru's needless infatuation with Haruhi. 5/5