My 2005 has 120000 kms on it and saw no indication the plugs had been changed, so I changed them with plugs from needswings. As above, some of them were harder to get out. I was surprised at the smoother idle that was immediately noticeable. Attributable to plugs, dielectric grease in connections, firmly connected boots, the TLC throughout the job? Who knows, but am glad I did it.