Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
The reason why is that with plugs in you can easily break the "ears" off the cam and elongated the hole the locating pin fits in. I have seen both but never done it myself.With no compression (plugs out) it ought to be safe to use BUT putting that caveat in an explanation people either dont read, dont understand or dont care.How many owners of cars with broken cam belts have ignored the OR FIVE YEARS bit