the trunk lid thing is actully a myth
"Two stories explain the rear spoiler. The common idea is that it's three feet tall so the trunk can open. However, it could have simply been mounted on the trunk in the production cars. An interview with the engineers at Chrysler, long ago, included a comment to the effect that as the numbers kept getting better as they raised the spoiler, until it was three feet off the car, that's where they left it."