style="MARGIN: 0in 0in 0pt; LINE-HEIGHT: 150%">            St. Louis--A man grips a muffler with determination in his eyes. The crowd cheers as the muffler comes to a halt after he skids it across the floor. Its distance traveled is carefully measured.              Each year, the North American Muffler Sliding Championship signifies the final day of Showpower, an undercar and transmission expo held each March by MD Publications Inc., publishers of Undercar Digest and Transmission Digest.             St. Louis played host to this year's show at America's Center on March 22-24.             "It was a 50 percent improvement from last year's show in Vegas," said Michelle Dickemann, vice president of MD Publications Inc. "When we look over entire attendance, as a rule 50 percent of participants are located nationwide, and the other half drives in."             The three-day event featured 19 training seminars that covered a variety of technical and management topics. More than 90 exhibitors showcased products ranging from brake lathe adaptors to shop management software.             Dickemann said the three presenters that drew special attention were Jerry "G" Truglia of Automotive Technician Training Services, "Telephone Doctor" Nancy Friedman, and John Thornton of Autotrain.             "Bringing in fresh, new people with new ideas and concepts to training is always a draw," she said.             Truglia's course, "Do You Really Know Electronics?" covered electronic testing systems that included hands-on training. Friedman, who has appeared on CNN and Oprah, discussed etiquette of business communication in her session: "The Seven Touch Points of Communications." And Thornton's session, "Re-Flashing GM," focused on the tools and procedures to properly reprogram GM on-board control modules.             "It's important any time you're working on an electronically controlled vehicle to have the ability to reflash," said Bobby Mace, publisher of MD Publications Inc.             Sunset Ford of St. Louis sponsored two training sessions: Ford Motorcraft Factory Authorized Training and Ford Factory OBD-II. During the two sessions, hosted at Hunter Engineering's nearby technical training facility, attendees had the opportunity to use Ford's OE scan tools and software during the session, Mace said, adding that troubleshooting techniques were also covered.             Rick Anthes, coordinator for the Ford Automotive Student Service Educational Training (ASSET) program at St. Louis Community College-Forest Park, taught attendees how to diagnose drivability problems using Rotunda IDS software and a laptop computer. The Ford Electronic Transmission Systems class was taught by Steve Goessling, an ASSET instructor at Forest Park.              On the show floor, attendees had a chance to win prizes of $500, given away hourly on the exhibit floor, and a grand prize of $5,000, Dickemann said. David Carlton of Muffler Matt in St. Louis won $5,000. Steve Morley of Jumper's Auto Service in Fenton, Mo., was one of two $500 winners, who had to be present on the show floor to collect their prizes.