It took four years, but Franklin County Commissioners have signed off on a plan to sell Cooper Stadium. The four-year long process was finalized yesterday. Arshot Investment Corporation plans to spend between $30 and $40 million to turn the Mound Street property into a racetrack and automotive center. The $3.4 million sale had been help up over noise studies and other wrangling over having a racetrack near the densely-packed Franklinton neighborhood. Some residents remain staunchly opposed to the track.