I ran with the BPU plugs and they fouled up with carbon (rough idle). Changed to stock ones before MOT and the car passed with flying colours. I am now BPU again and I am running with the same BPU plugs, which has some carbon fouling. The car runs great and pulls awesome, just a minimal hiccup on idle from time to time. I have ordered a new set from Whifbitz and my question is as follows, Should I leave the car until I get new plugs (4-7 days) or am I safe to use it with the current BPU plugs? I just want to be 100% sure as I don't wan't to break anything.
ps: They are NGK iridiums.