No offence Luke.A, but in your very first post on this forum, you said, " I have only ever ridden a 49cc scooter hahahah" I Highly doubt you will need any kind of performance upgrades at all rofl, expecialy on an engine like the z160ho, ( CAPACITY)
Maximum Speed: >120kph*
Maximum Load: 140kgs_
like rach88 said ride the bike till it breaks then upgrade the broken part.