I just followed your write up on my 2004 330i ZHP with 126K. Bought the car with 105K and did the cooling system right away. I should have done the plugs a few months back when the valve cover & gasket were done, but I was traveling and had to have my mechanic do it. Took me less than an hour today to do the plugs. HIGHLY recommend removing the cabin filter housing and battery cable. It's really easy. Anti-seize is a must! Thanks for the DIY!