Spark plugs generally don't have *too* much impact on the overall running of cars like they used to. Ignition systems are such high energy that as long as you are running the right heat range specified by the car manuf., thats the best you can do. Its kind of like asking "What brand of oil should I use". The answer is use what you want and change it often. Spark plugs are kind of the same way....
NGK's heat range scale is opposite of Bosch's IIRC, which is why the numbers appear different. That being said, stick with copper core plugs only on these engines. Platinum and Double Platinum plugs sometimes do cause issues on cars older than 1995, and thats what they always try to sell me first.
I accidentally put 70,000 miles on my last set of spark plugs because I thought I had changed them halfway. The were toasted, gap a mile wide, NGKs, and one of them was a completely different NGK model (I think the parts store screwed me) than the others. I replaced them with new Bosch copper cores and the engine ran....exactly the same.
I would check the condition of the rotor and cap as far as looking for issues in the ignition system. They are critical to smooth spark in all situations. These cars are higher RPM cruisers so they tend to burn through caps/rotors a little faster than other cars.
If you went to the dealership parts counter they would sell you F8DC4's. F9 DCO must be an superceded part number because none of my parts sites stock them.