I'm in the UK. You can even get a C180 here.
My C200 is slow. But over here, smaller engines are the norm in all cars, petrol prices being so high (about US$5.50 for a gallon!). Most people have a 1.4 or 1.6 litre car, so even a 2.0 litre is probably a bit larger than average.
My car develops 136 bhp and 140 lb/ft of torque. It will do 0-60mph in about 11.5 secs. Unless you rev the nuts off it, it has only, shall we say, gentle pick up.
The other thing you have to remember is that Euro cars have a much lower specification than US cars and so are significantly lighter: no heavy electric seat motors and so on. Also Euro smog gear places fewer restrictions on an engine's breathing. And finally, Britain is a small and very crowded island: you just don't get a chance to stretch a car's legs!