The quest to sell more Nissan cars in northeast Ohio spilled into federal court this week, as the owners of four dealerships around Cleveland said they were unfairly burdened by financial incentives the car manufacturer gave to a competitor. Jeff and Matt Greenberg , who own Nissan dealerships in Bedford and Mentor, and Mike D'Amato , who sells cars in North Olmsted and Sheffield Village, allege that Nissan North America illegally gave millions of dollars to Bernie Moreno.