m20b23 - m20b25 swap help

[blingsta]

hi guys... im helping a mate out with this conversion.. everything is done and ready to go, but there is just 1 problem.. body loom plug is the old rectangle plug and engine loom plug is the normal later round c101 connector.. ive just the wiki and it looks pretty straight forward !! its just a matter of connecting 9/10 wires together.. but im a bit sceptical as the round c101 connector has more than 10 wires ! surely some of the wires dont stay redundant do they?