In determining whether good cause for the refusal to honor the succession exists, the manufacturer or distributor has the burden of proving that the successor is not of good moral character or does not meet the franchisor’s existing and reasonable standards and uniformly applied minimum business experience standards in the market area. The provisions of sections 42-133y, 42-133z and this section do not preclude a new motor vehicle dealer from designating any person as his successor by written instrument filed with the manufacturer or distributor and in the event there is a conflict between such written instrument and the provisions of these sections, the written instrument shall govern.