Superior Industries International Inc. continued to show improvement in its quarterly earnings despite weather-related disruptions at its manufacturing plants. The Van Nuys-based maker of aluminum wheels reported net income of $8.1 million, or $0.29 per diluted share for the quarter ending March 31. For the same period a year ago, the company had net profits of $8.9 million, or $0.33 per diluted share. Superior saw its first quarter sales increase by 26 percent to $189.5 million from $150.2 million the year before. The 17 percent increase in unit sales volume kept pace with the 16 percent in total production of passenger cars and light-duty vehicles in North America. “We kept pace with the market despite taking a full week maintenance shutdown and incurring some weather related disruptions in all our plants,” said Superior Chairman, CEO and President Steven J. Borick. Shut down costs in the first quarter of 2010 were approximately $600,000, the company said. Mark R. Madler