Why are automakers still building vehicles which are grossly overpowered, & dangerously exceed top legal speed

Cite your fellow citizens, not the manufacturers. They build what sells. Judging by the sales of the high powered retro-cars like the new Mustang this trend will continue despite gas prices, etc. Also quite a few out there have large SUV's and Pickups with very powerful engines to pull their toys around. Things like boats, trailers, campers, dune buggies, motorcycles, etc. Lets face it part of this countries success is the consumer dominated market where we have to have the biggest and greatest of everything. So like it or not, it is the consumer that can change the manufacturer, and as long as they follow the Federal Guidelines for product safety they are pretty much safe from lawsuits.