Honda now uses the 2.2L engine in the American S2000 and the 2.0L engine in the Japanese market. I have no idea what they sell elsewhere in the world. The justification for the higher displacement is more torque at lower RPMs, meaning that in daily driving you don't get bogged down or need to shift every time you want to accelerate. The trade-off of the larger displacement is a lower max RPM.

(Apparently, due to funny Japanese taxes, it's significantly cheaper for them to sell a 2L than a 2.2L engine in Japan. Conspiracy theorists talk about them wimping the car out for clueless U.S. drivers, but I think it has as much to do with the way the taxes work.)

Meanwhile, on "slipping" vs. "dumping" the clutch: what I meant to say was, to get a good launch out of your car, you don't necessarily want to just rev it up and immediately release the clutch. This might (a) destroy your transmission, (b) burn out your clutch, and/or (c) deliver more power to the wheels than they can deliver to the ground. Your goal, if you want the fastest possible acceleration, is to have the tires just slightly overpowered. Depending on your engine, tires, etc., this may change how fast you release the clutch and at what RPM. On my Z3 (2.8L 6cyl), the answer seems to be revving it up to around 3000rpm and releasing the clutch over about 1 second while keeping the engine RPMs steady. On a friend's Honda S2000, he has to do something like that at 6000rpm.