Joe if you will street drive the car you will be much better of with the twins. Mark can jump in here, as he has been there, with a single at those power levels you start running into inlet temp problems for a street driver.
For what you will be doing I think the perfect rear gear is 3.55 for the twins. I have 3.73 but will be running a 28 inch tire and I may go to 3.55, I’ll have to see how everything works out. The taller gear loads the turbo much better on launch and creates boost much faster.
Earl