Hi Andy,
The simulator facility is really useful when you train your own drivers from the Youth Academy.
It is almost the last facility to upgrade, just before hospitality.
Now I suppose the Boost Facility is the Technology building.
This one is quite important because it provides enhanced DRS and KERS, so you can go faster than others have better results.
I really felt its usefulness when I entered Pro and saw everybody passing in front of me in DRS zone and going like 3 seconds before me instead of merely reaching me.
The importance of buildings is usually this one:
- Manufacturing
- Design
- Technology
- Youth Academy
- Simulator
- Offices and hospitality
The 3 first can be in different order, depending on managers, the YA and Simulator go together.
You will get Talent 20 drivers quite easily with a YA level 13, hence upgrading it slowly with the simulator.
I hope this helps, have fun racing.