Hey Chuck,
I faced a similar issue with my R32 a while back. It was misfiring pretty badly even after I replaced the coil packs and sparks (not exactly easy on the wallet when you need six of each). The misfiring errors persisted even after scanning, and I was getting frustrated.
Eventually, my cousin, who knows his way around cars, heard a slight hissing sound near the back of the engine. Turns out, there was a split air line going into the brake servo. I'd recommend thoroughly checking every single line under the hood.
If that doesn't uncover the issue, considering your love for the car, my suggestion would be to use a local flatbed service to take it to a reliable specialist. Unfortunately, you are far from Wales, but there's this fantastic place called "Euro Performance" here. Gareth and his team worked wonders, completing a full engine rebuild on my R32 in just three days.
This kind of work is their specialty, and if they can't fix your car, I doubt anyone else can. You might be looking at a few hundred for the flatbed service, plus the repair costs, and then the return flatbed. However, they'll book you in, fix your car, and it ultimately comes down to the investment.
If you're open to this option, tell them I recommended you. They'll treat you well, recognizing you as a fellow car enthusiast, although it won't necessarily get you a discount.
https://euro-performance.co.uk/
