Despite Grumpy there, welcome to XOC.

This is my personal advice.

I don't think that the Platinum Plugs need to be changed at 60K miles. And if the the O2 sensors are working, then they probably don't need to be changed. You could cause a problem changing them out with aftermarket units. And, you'd have to change out all 4! Not worth it.

Changing your fluids (diffs, t-case, trans flush, coolant, brake fluid, oil) and rinsing your radiator fins out with a garden hose (be careful not to bend any fins with high pressure water) would do your X a great service. A fuel injection service along with a fuel system cleaner such as BG44K, wouldn't hurt either.

But the plugs, eh, I'd leave 'em. O2 sensors, leave them as well.

My X didn't come with an owners manual.

Oh, and others may agree or disagree. It's just a personal opinion.