The US emphasizes low production costs and ride comfort and cares less about performance than Europe or Japan. In addition, we have different emissions regulations.
Therefore, our shocks are mushier, our brakes are spongier, our engines are usually less powerful, and our seats are wider than non-US versions of the same model.

that and oddly enough american drivers DO NOT want to hear their brakes work. so US auto makers use alot of different materials in them to quiet them down. european drivers are the exact opposite and would perfer to hear them work. so they can censentrate on performance a little more.