Hi Pablo,
I am not from Laminar Research; just a flight simmer from downunder.
You can install as many copies of the one legal version on as many computers as you. However you can only run one version at a time to be legal.
To run the digital download you need to be connected to the internet at all times. The software performs a silent back ground check to determine that your copy is legal. If you are running two or more copies at the same time using the same product key you will be automatically shut down and possibly permanently locked out from your one legal copy.
Glenn