The tappets are easy to do, take off belt etc then rc release cam carriers, remove cams, best to mark positions on things as well.
I find that by drying the oil off the top of tappets and using a "GRINDING TOOLS", suction end will lift them out without having to grip them.
Put new ones in and put all together, torquing as you go.
The oil can certainly make a big difference to tapping especially the wrong grade, there are better oils than MOBIL ONE, but this is a very personal thing, so long as it is SYNTHETIC and POLY-OL ESTER this is what is important, although I think this oil is TRI-ESTER ?
tabetha
ps this is a quick run down, if not sure get someone there to help as you do not want the pistons and valves to have a fight, as it will be your wallet that loses!!!