[QuickLTD]

For those who did not read the article here is what they said regarding the aero:
Porsche 928 enthusiasts have long questioned whether its design caused enough aerodynamic problems to affect the performance relative to other sports cars. The first 928s suffered from a large frontal area for a sports tourer, and a strangely angled tail that did little to manage the air flowing around the vehicle. At 75 mph, the original 1978 928 was losing 28 hp to drag, a noticeable deficit given its 219-hp engine.
Two years after launch, Porsche added front and rear spoilers to better manage aerodynamics; later models included longer rear sections that improved air flow along with upgraded engines that had more grunt to overcome such losses, topping out at 345 hp by the time production ended in 1995.