the hf is so slow due to the 2.9 final drive in the transmission the car is built for economy .....high geared tranny and mpfi with egr. it sports 62hp while the dx sports 92 if you were losing to an hf you car sucked!!!! there is no reason for a dx to lose to an hf unless the hf has had a new head, manifold, ecu, transmission, intake , full exhaust.or you just can drive .my god have you seen the plenum and throttle body on an hf...its most definetly a "high fuel monster" the only way its high fuel , is if its high fuel economy. 16 valves is always better than 8 . you flow more air through the head . thats the reason ppl with SVO mustangs get rid of there 8 valve heads for a 16 valve volvo head.. on top of more flow through the head you also get a swirling action of air and fuel due to the cam lobes on the intake side be a slightly different lift.