Great Advice!! 70k on my 2006 ZX3, old plugs were clean, showed about 050 gap. Put in 103's at .055. Mileage on first tank was mainly highway, with some city was 36MPG!! This is with the winter blend which has been giving me 30-31MPG. Can't wait for summer, I think if this holds I'll be able to break 40MPG.
Plugs were extremly easy to change.