Custom motorcycles, while small in number, are still a vibrant part of the SEMA Show and its displays. SEMA showcases not only car and trucks parts, but also those for bikes, trikes (Bombardier's new three-wheeler was a particular hit with the crowds) and marine engines ... In fact, many of the stoutest racing engines get their heaviest testing while powering boats through rough water ... Lessons learned from those beatings, about the toughest you can give any engine, are used to build better racing engines, and eventually those experiences "trickle down" to the stock engines engines in our street cars.