After viewing some pics it seems that on stock suspension the AWD gap (ya i know its big) looks better with the 19" wheels. I don't know if the smaller sidewall/bigger wheel combo but that's my take.

What do you think?

They look the same like 17, I mean you have the same gap. I have 19 on my X.

^ WHS, as long as the tire has roughly the same overall diameter as the OEM set-up.

Here's something to consider, smaller wheels actually make a car look dropped more than larger wheels.

+1...
The size of wheel shouldn't change anything.
With 19s or 20s the tire aspect ratio is lower to maintain the same overall diameter as OE.

i know that's certainly the case for car that has an average gap, but for some reason since the G has a huge gap (even larger than 335xi) 19's seem to fit it better than 18's.

could be just me...

It's not just you, it is a huge gap.
The only effective way to improve that is by suspension mods.

hahaha, only car i can fit my whole fist into the front fender.

You will never get rid of a gap by just changing the wheel size... To eliminate the gap you will have to purchase some suspension mods...

Springs, Coilovers, struts, etc...


BTW- you have a bigger gap than Sport models because you are AWD...