I am very happy with NGK plugs especially with the Iridium tips. In the TC I have: NGK plugs BPR6HIX In both my TD and 74 Midget MkIII I have: NGK plugs BPR6EIX With these I notice all the engines run even smoother, but I can t say why. Recently drove a 600 Km outing with all three cars and never sk...