When the wheelbase and suspension pick up points are the same it us the same. Platform engineering is not quite the same thing as sticking a different engine and gearbox into a car. The "platform" is not just the same it is identical.
Sure, you can get bits and bobs on your Macan that you would have to add to your Q5 but basically Porsche is building a Q5 variant. I'm willing to bet you can fit any Macan bit to your Q5 should you wish to waste your money.