What you'd need to know first is that you should match your plugs with what was originally in the engine. Same with ignition wires.
You might get an unnecessary scare or poor performance if you try to use something fancy. Don't know why. It's a computer managed engine is all I can say.
Change the oil at respectable intervals. Throw in a new PCV valve to assure that the crankcase is able to vent freely. Keeps the oil cleaner for longer.
Seafoam that bad boy.
I know you can easily change out the front and rear differential fluid using a suction pump, but I'm still looking at safe alternatives to flushing the trans w/o taking it in. Probably just recommendable to take it in. If the fluid is full and looks healthy, you may already be in good shape. You can check out the filter though.
It may also be time to look into changing the timing chain.
I'm sure others will add their thoughts and experiences as well.