You are probably correct in your thinking that the highway driving will not benefit much from the shroud. You might go one further and remove the fans as well and not suffer any more.

If it were me I would stick with the stock setup. Second guessing the factory engineers will not likely produce all around results that are favorable.

Good luck.

Tom W

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.