DETROIT — Spring is a special time of year on Detroit’s Southwest side, known by many as Mexicantown. It’s a time when Mexican Americans and other Latinos wear their culture proudly, usually starting with a Cinco de Mayo parade along Vernor Highway, the largest such event in Michigan. Large chunks of the main drag are blocked off, as girls in flowing folklórico dresses and young men in mariachi garb make their way down the main drag, while restaurant owners turn their parking lots into makeshift cumbia clubs. And then, of course, there’s the Blessing of the Lowriders.