I may be a little late to this argument, but here it goes.

Sure, 2,000 HP sounds impressive by itself. However, specific power output in terms of HP/Liter is a measure of how good an engine is at using its displacement to make power, and in my opinion, provides a more objective way of comparing engines than just power alone. The car in question makes 2,000 HP with 4XX cubic inches of displacement. At best, it's 400 ci which, according to Google calculator, is roughly 6.555 L. 2,000 HP / 6.555 L = 305.1 HP/L.

A 1,000 HP Supra (2JZ engine displacement = 3.0 L) has a specific power output of 1,000 HP / 3.0 L = 333.3 HP/L.

A 1,000 HP Skyline (RB26 engine displacement = 2.6 L) has a specific power output of 1,000 HP / 2.6 L = 384.6 HP/L. Maybe I'm missing something, but it looks like Japanese cars are still kicking the **** out of American cars, at least in the specific power output department.