I would look at it from another perspective.
If you're building it to compete in a class, then you should determine how much power you need to be competitive, and build to that target goal.
If it's just a street car, then it will likely come down to the same determining factors that go into many street builds...... Which usually revolve around the theme of what your tolerance is for how rowdy it can be. In this scenario, you build it according to what you think you can live with, and that engine combination just makes what it makes.