My 250 choice is largely MPG driven. I drove a couple of 250's which seemed fast enough to get a speeding ticket. I bet the 3.5 liter screams...
On the engine topic, is anyone else amazed how much power they get out of these small engines nowadays? As a young person, I had a '67 Mustang w/ a 200 cu in 6 cylinder motor, and my friends made fun of the tiny engine in my car. If my math is right, a 200 cu in engine is ~3.3 liter, which we don't call tiny.