Here's my findings on the lower runners..
Note I only took photos of the "width", vertically all ports were symmetrical.
Here is cylinder 3 at the head mating surface. Measures 53mm at it's with as does the actual head.
Now at the runner side of things, cylinder 2 and 3 measure ~51mm. smaller, but 2mm is not much to scuff about
Cylinder 1 on the other hand is right on in dimension.
But, 4 is actually wider for whatever reason, but still within 3 mm.
I'm actually very impressed with the runner casting. No jagged edges and super consistent throughout. There is no choke whatsover throughout the runners. There's some angles involved, but it looks as though nissan kept it one size all the way. No reason they wouldn't.
Same size runners means there is absolutely no restriction of air going to the head. Fluid flows the same velocity no matter how many bends as long as the pipe size doesn't change. Larger will slow velocity, and smaller increases. So unless you port your head there's really no benefit in trying to fit more volume through it when the restriction is the head which flows amazing stock.
(excuse the oily intake) VE intake ports are freaking awesome.
Now mind you I don't disagree modifying the runners and doing some work to them, but the openings are completely adequate that are to meet plenum floor.