I am about to get a larger throttle body.
The standard one is 60mm I am lend to believe.
Do I need to machine the intake manifold?

I am told that on most cars... the intake manifold could match the throttle body and be also 60mm. Thus having a bigger throttle body wont make a difference without machining it.

Thats right if you go a larger t/b you'll have to machine the plenum to suit