Since the release of the IS 250/350 specs there has been a great deal of chatter about the horsepower of the new cars, specifically with reference to the 250 being underpowered. I really don't know too much about cars and so I was wondering if anyone cared to explain the real-world advantages of say having ~300 HP vs 204. Obviously racing-enthusiasts need the boost but what about just driving in the city or on the highway. Presumably merging/overtaking is easier (but is it really that hard to merge or overtake w/ 204 HP?). Anything else that the extra power can do for you?