I'm sure I will now here otherwise. Pistons, cylinders and rings do not show signs of wear like the air cooled engines. The oil consumption is typically not high and the pistons and cylinders do not need to be replaced normally unless over heated or you are doing a total rebuild. There couldn't be a better time to replace the water pump or any weak exhaust pipes, injector seals and high pressure injection hoses. I recommend using only OEM sealant when resealing cylinder heads.
Some silicones can be corrosive when used on aluminum.
Most coolants are now suited for aluminum engines, so read the label on the coolant you are thinking of using. Corrosive inhibitors can be purchased to supplement the coolant, but I don't think it is necessary if the antifreeze is changed every two years. The lifters are hydraulic, and tired lifters take longer to pump up, if they do at all. Lifter replacement is judged by how long you hear the ticking when the engine is cold. There is no extra labor involved to replace the lifters when the heads are off.