Hi TOM,
For some people it has more to it than, 'just the sake of it'. These cars are not always about ultimate black and white performance. Some builders will chose style, comfort, sound, and even a certain look before ultimate efficiency. I will be the first to admit that the LS based engine is the most efficient unit (I have one in my car). But to me ultimate performance does not and did not drive my every decision. Now if it was a race car.....then I would have decided solely on the cold hard numbers. But some of these cars are asked to be more diverse and satisfy more than just race/track cars.