This would never work but would be fun to poke the SCCA bear. I was just looking at STR inclusion list for some other car and saw this:

RX-7 (non turbo)

Not generation or year specific

Now with being able to run headers and any intake in ST, could you make an FD naturally asperated and be legal?

Hear me out...
Superior suspension design
Loss of weight of all the turbo gear
Reliability
Power would be a bit of an issue but on a flowing course....hmmmm

Here is the fun bench racing for the day.

 

No you cannot , modifying the turbos would alter the car beyond the scope of the rules , Turbos are not concidered an exhaust peice . they are turbos .

and even if you did you'd have an underpowered S2000