At that level, the cars that run that fast and are driven on the street don't last very long.
The guy that built the last Regal I had has since moved on from V6s to an SB2.2 94mm powered Regal that has been 7.77, it ran that for about a year, now he's moving a lot of weight out of the front to be competitive. In doing so, he's also ditching the radiator so it won't be able to make much of a drive on the street. The car will still have tags and insurance, but it won't be able to be driven as it used to be.
That said, there is no such thing as a tame 7 second car.