2 things that should be done to every kit.
match the transfer ports and match the intake port to the intake manifold. depending on the kit you really shouldnt be porting your intake window. you can roughen up the passageway to help atomize fuel if you are running piston port though. what you should be paying attention to is the exhaust. every kit out there can be opened up at least 1mm on each side and that always adds a couple mph.