Actually, I was under the impression that the single runner intake on the later 3L motors was optimized for mid-range power (right where the ATX Taurus would be using it), and the dual runner setup (especially the SVT setup) was optimized for top end, as well as a bit more low end power on the smaller displacement motor.
The thinking is that the long runners on the dual runner setup are best for low end, and the short runners were best for top end. In the single runner manifold, the runners could be considered "medium runners" (not as short as the dual shorties nor as long as the dual longies) and would be at their best in the midrange.
However, I have yet to see a dyno plot that compares the two setups, so it's all theory for now.
