If I was planning to use the car mainly on track, then I would be very tempted by a BEC. The light weight, sky high revs, lack of reciprocating mass, and the sequential gearbox are at home in that environment. If, however, I was planning to use the car quite a bit on the street, then I’d go for the Duratec. Which is exactly what I did.
The 2.0L and 2.3L share the same head and bore dimensions, but differ in stroke length and block height (the 2.3L is about 14mm taller.) 250hp is easily, although not cheaply, achievable in either configuration. As you would expect, the smaller engine makes power with revs, whereas the stroked version relies on big gobs of torque. I currently have a 210hp 2.0L Duratec and love it. I wish it was a bit more frantic up top, but the broad torque curve is pretty compelling. With my gearing, 7500rpm in 3rd is 102mph – so not particularly short – yet starting in 3rd from a dead stop isn’t a problem and still results in strong acceleration.
-John