If you need more power, upgrade when it might need new parts anyway.
Why not a 836cc kit? like this..
http://cbrzone.com/sohc.htmlOn top of this ported head.
I have similar on my bike and it turned to be a very good touring machine. 2 persons + luggage on the bike, driving all day long (except for gas stop) 150-200km/hour, no problem with nice acceleration. My cam was mild, 0.360 lift, 270 degrees duration. Perfect for street and touring.
I'll go for a hotter cam now since my touring days are over with my bike. I need new thrills next time on the streets again.