New 2004 s2000 2.2L vs 2.0L Previous models
Dyno results show 265-270 at the flywheel (220 ish at the wheels)

http://www.s2ki.com/user/content/view/full/253/ for links to articles & pics of the new design.

2004 S2000 Engine Design - Keys to Note:
The engine code designation is F22C1 to denote the 2.2 liter size.
Cylinder bore is 87.0 mm and stroke is 90.7 mm to have a 1:1.04 bore-stroke ratio. The slightly undersquare design provides better torque at lower rpm.
For comparison, the 2000-2003 model's cylinder bore is 87.0 mm and stroke is 84.0 mm for a 1:0.96 bore-stroke ratio.
Continues to use traditional VTEC instead of i-VTEC as on the K-series motors.
Where F20C was known to offer significant power from 6000 rpms onward, the F22C supposedly comes on very strong at only 3000 rpms.
Honda asserts that the '04 S2000 offers measurably stronger acceleration in each gear