-1 in front you can keep your stock chain (you'll have to adjust it obviously) so you can see if you like ratio change or not. +2 in back and you'll need a new chain. Each option is almost identical as far as increasing your gear ratio. And doing both at the same time and going with 520 (thinner, less rotating mass) width chain is a popluar choice on 600cc bikes.

It'll make a noticeable difference, hell i thought just -1 in the front was huge difference. I eventually went back to my stock sprockets because i enjoyed cruising at a reasonable rpm on the highway.