New Ferrari Owner - Misfiring Troubles - Where to Start

Good Evening All, Like many of you, I have always wanted a 308 and have spent the last 5 years casually looking and the last 2 years in earnest. This August I purchased a 1985 308 GTS QV for a mechanic / dealer shop that I know. The car had a good pedigree and had been serviced by the shop for the last 21 years with the same owner (he was the fourth). Approximately 7 K miles put on the car from 2003 - 2006 and then 2 K miles from then until now. The car had 58800 + miles at purchase. The car had lived its entire life in California, with the exception of a brief stint in Oregon from 1999 - 2001. I have a lot of records for the car. It has been routinely serviced with bi-annual smog tests since 2003, appropriate timing belt service, fluid service and maintenance.

I test drove the car and it drove great. No issues with the 10 mile or so drive on city and highway speeds. Engine compartment clean and a very good external / internal appearance. Very happy with the car and very happy with the maintenance it has routinely undergone.

It had a mini-PPI at the dealership, annual service with a belt exchange and passed smog. I took it home very happy.

Bottom line, approximately 60 miles into driving this car, it began to misfire. Subtle at first, at the top of a steep hill.. almost like the tank was near empty or some old gas or debris had fouled the injectors. It stalled once or twice and then it made it home.

Next day, I filled it up with new fuel - 91 premium and took it for a drive and 10 to 15 miles into it on the freeway, it began to misfire, a little at first, but by the end of the 20 miles drive (already had committed to a loop on the freeway) it had lost significant power and the CAT was running hot. I now know that likely the front bank (5 -8) were not firing leading to raw fuel heading to my CAT. It was a hot night, so I thought heat may be affecting my ignition system. The next morning, when it was cooler, the major misfiring occurred right away so it was not heat related.

For the next couple of days, I researched the forums and reviewed the internet and youtube. Definitely seemes like something was going on with the ignition system. I started with making sure the sparkplug extenders were well seated and just by doing this, the car ran like a dream for another 10 miles or so. Later that day, when I went to take her out again, the initial problem repeated itself.

So I am looking at some issues involving the ignition system and one bank of cylinders. I reached out to the mechanic / dealer shop but did not get any satisfaction, except to "bring it in." I am a little apprehensive about this given that this car was supposedly good to go. This is my default option, though.

As a younger man, I worked on several cars and always liked the idea of my own maintenance. Since I have always pined for the 308, it is definitely my intent to be a hands-on owner... I just was not expecting this to be needed week 2 of ownership.

So my question for group consideration. How would you all approach troubleshooting this problem. This is was I was thinking.

1) Pull and examine all of the sparkplug extenders and ignition wires for corrosion and integrity. Replace or repair as needed
2) Pull and inspect all 8 plugs, maybe they were last changed in 2001 at 49 K miles
3) Pull, inspect and clean rotor cap and points
These I could do on my own.

Then need to contemplate troubleshooting the coils?
Any other thoughts?

I did a deep dive into the recent service records over the last 20 years and it appears as though this 308 has had intermittent problems with it "A" bank firing? so this may not be a new problem.

Any constructive thoughts would be appreciated.
Thanks