Euro-spec versus US-spec: compression, cams and power

Euro cars are consistently described as meaningfully quicker than US versions: higher compression (10.5:1 vs 9.7:1), bigger cams with more lift and duration, less weight, and roughly 185hp against the emissions-choked US rating of 167hp. Commenters note the US power deficit came from tighter emissions controls and that a Euro downpipe / cat removal recovers much of it, though higher-compression pistons mean cats alone don't close the gap.