When it comes to quarter-mile times, it's a lot more about engine output graphs than it is power/weight ratios. Transmission shift points, gear change times and differential choices play a big role as well, but where the engine is involved, it's all about output curves. Put too much horsepower and torque at the high end, and it all comes in one big rush before you have to shift and then you lose it all. It's the same problem the S2000's always had. If you want to accelerate past anything at highway speed, you pretty much have to downshift so you wind up at the top of the RPM curve.
As an example, the R&T review that's in the media section has the Mini Cooper S Works and the GTI clocked in at the same 0-60 time and keeping pace with each other until 80 MPH, even though the Mini weighs 550 lbs less and puts out 207 HP. The big difference is that the GTI delivers its 200 HP at 5100-6000 RPM and 207 ft-lbs of torque at 1800 RPM, all the way to 5000 RPM, while the Mini only delivers top horsepower at the rev limiter of 6950 RPM and only has 180 ft-lbs of torque at 4500 RPM, close to the limiter. So the GTI, while weighing much more and producing slightly less power, can create its maximum power over a longer period of time and has much more rotational force available over a bigger RPM range to deliver that power to the road.