On the GNTTYPE website it says..Cars running 12.99-13.50 seconds or faster should use R43TS or CR43TS plugs (one heat range colder) and 12.00 and faster cars should use AC R42TS or CR42TS....
But if i'm in between the two I assume I use the 42's? Whats so different between the 42's and the 43's?
But if i'm in between the two I assume I use the 42's? Whats so different between the 42's and the 43's?