What can I do to bump hp up to 27-30..Don't want to go to crazy to effect the reliability.

talk to SETX performance----you can do SOME mod work on the Honda but not as many as the other brands.....aftermarket exhaust is hard to find. You can't reject the Honda carbs except for high or low altitude's.

I have decked the head's (.005) polished the exhaust side,shimmed the valve springs and a set of custom made dual's exhaust. It has really helped with the in consistent idleing and other "small" quirk's. Hope this helps