http://www.mercurynews.com/news/ci_5834060?nclick_check=1 snippet: The San Francisco 49ers finally have the pieces in place to make their 3-4 defensive system work. The team has been trying to transition from a standard 4-3 set since Mike Nolan arrived as head coach in 2005. Nolan built his NFL reputation as a defensive guru, but the 49ers have struggled to implement the scheme he favors because they've lacked suitable personnel. But that no longer appears to be the case. After bringing in four potential starters in free agency and using six selections on defenders last week in the NFL draft, San Francisco's defense now is built for a base system that features three down lineman and four linebackers. "I like the way right now it is shaping up," Nolan said Sunday at the team's minicamp. "Weve made some good (additions). Those guys make the difference in a 3-4."