Thinking of doing this just becuase I have a 3 litre box here.

Just a quick question will it rev higher in 5th?
And technically it should be quicker in 1st and 2nd?
Will an EVO clutch fit fine? Apart from the usual rubbing they have on the 3.5 boxes? Like is the bell housing smaller on a 3 litre box is what I'm trying to say

Its been touched on before... Google "3 litre manual 3.5 aussiemagna" and youll find plenty

Will bolt on

Evo clutch will give you a difficult pedal adjustment and you may need to trim the inner bell housing, also flywheel will need to be stepped.

Std 230mm clutch in Exedy will be fine for any NA motor

Yes the car will rev slightly highter in 5th due to the box's ratio but this wont have any noticable effect on performance or econ.