I can see abolishing the speed limit, but only if you make the penalties for injuring somebody in an accident extremely high... as in if you destroy somebody else's life,limb, or property, you spend the next 30 years of your life behind bars...
until that happens, there is no need for a car over a v6... unless you're in a place with pretty much no speed limits (midwest) or are legally racing... but here in the suburbs and in the city there's definately no need for the power...