Spark plug OEM Toyota or OEM Honda

I have an aero 50. I don’t recall what’s recommended on it, but when I was living in the Pacific Northwest, I found that while using premium, it ran significantly better. Smoother idle, better acceleration.

I remember the first time I did anything besides oil, it was spark plugs and power steering fluid on my old accord. Starting it up after had me nervous, second guessing everything I did.

I was looking at pictures of the V12 engine found in the Toyota Century. Then I noticed the spark plug/coil arrangement: Interesting.

And timing belt, and spark plug change every 90 K miles or so.

Sounds like it could be a spark plug. For some reason the Prelude likes to eat through them. Shows the exact same symptoms you describe (loss of power, different exhaust note).