So, I just did my maiden oil change yesterday with the RL 5W30 HP oil and the RP 20-820 oil filter and have about 300Km's so far on it.
I was using either Castrol or Pennzoil 5W30 synthetic and a Delco or Mopar oil filter, and doing 6,000km intervals. My oil was always clean and my engine performed well with little in the way of any abnormal noises internally. But, I wanted to ensure longevity, and at almost 120,000Km's in just over 3.5 years of ownership I felt it time to put the best oil and filter to use and keep my HEMI happy.
The only hiccup was initially getting this new wider oil filter on as there is wiring of some sort that runs right up beside the oil filter base. I had to tuck it up and out of the way, and ensure it wasn't getting pinched between the oil filter and side. All was good and no issues or leaks.
Wow....what a huge improvement on feel, performance, and just a happier and more responsive engine overall now. I'm going to extend the intervals to a maximum of 8,000Km's (5,000 miles) based on what the brain trust in this forum indicate as a good timeline on this combo of oil and filter.
Thanks again to All here for the great information, hands-on experience, and recommendations.