It really baffles me that many of the new cars / trucks have 100k plugs now and we still have to do this every 30k. For those of us that drive a whole lot, it matters. Anyway, I have seen some previous threads that indicate that there are 3 of one type of plug and 3 of another. Should we reuse the same 3+3 combination or simply get 6 of one or the other? What brand and model plugs are the 3+3 type. Are they pre-gapped? Thanks in advance.