This could possibly the dumbest question on here so please dont flame me but does a lower profile tire on the same size rim make the car any lower i.e. 235/45/17 vs 235/35/17?

 

with the sizes you listed yes, however it will look like the wheels dont belong on the car or you will hve major gaps in there

 

I planned on going from 45 to 40 do you think that would be to much of a gap?

 

Kind of. You have decreased ground clearance by 23.5 mm (difference in radius not diameter).

But that is not the objective of mods such as springs. Shorter springs will drop the body on the suspension. The distance between the base of the spring and ground remain the same.

Does that make sense?

 

So lower profile tires lower the skirts and bumbers to to the ground but has no effect on lowering the wheel well or body to the tires?

 

Yes, it will actually make the wheel gap larger.