If we get a choice of Twin Turbo,can we at least have two Turbos that can be Seperately adjusted,So that in a engine,we can have an Economy Turbo while the other one is a Perfomance turbo.
We don’t know how we will be doing this yet, subject to be discussed before we revamp the forced induction option later down the line 
You need consider the general lack of UI space.
That would be great if it was put in game, you could almost eliminate turbo lag because you could have one turbo that gives optimal performance at low rpms and one at higher rpms. Like on the VW Amarok and some others I can`t think of right now.
The technical term you’re looking for is “Sequential Turbos”, which apparently are a “Probably” item at the moment.