To my knowledge, the rotor button, wires or coil has not been replaced. Last time I replaced the plugs, I did replace with good ole NGK. I definitely agree with you on that.

My 98 does not require high octane, however, I have found that I get more mpg when using it.

I have not adjusted my valves. Is that something that anyone should try to tackle ? I am somewhat mechanically incline. I am definitely not a mechanic, however, I know my way around a car pretty well.