Some mechanics don't know how to handle Bosch plugs and try to re-gap them and then blame Bosch. This damages the very thin center electrode and cause problems. You should not re-gap Bosch or NGK Iridiums with very thin center electrodes, that's what the instructions say if people would just read them.
formatting link
Denny Hamlin Wins Sprint Cup Race for Third Victory on Bosch in 2008 Martinsville, VA, March 30, 2008 -- Denny Hamlin won the NASCAR Sprint Cup race Sunday at Martinsville Speedway driving a Joe Gibbs Racing Toyota Camry equipped with Bosch spark plugs. It was the fourth career Cup win for Hamlin, who finished just .398 of a second ahead of runner- up Jeff Gordon for Hendrick Motorsports, also sparked by Bosch. The Hendrick combination of Gordon and two-time defending series champion, Jimmie Johnson, had won eight of the last 10 Cup races at the Martinsville oval. Sunday's race marked the third victory of the young '08 season for a Bosch-equipped entry on the Sprint Cup circuit.