Hi, thanks for your reply, I thought I might get a set to be refurbed, so it would be a firm definite "no probs here" situation, I fancy I have one maybe two dribbling, the power is great but every now and then I can feel it's not running on all six, and at night the exhaust that I can see in the rear view especially with someone driving behind with their headlights on, is like puffs of smoke like from a gun. Please direct me to Karl, I appreciate your help, thanks and best regards.