Hi, Ron. Indeed,this has always been, and will always be, a topic for debate...a few facts, some good science, a lot of pseudo-science, habit, folklore, tradition, politics, "oil religion", and economics in my opinion.
Keep in mind that YOUR engine was developed using Mobil 1 0W-40. So, why change? One reason may be track use and/or other duty driving...also hot climate. In those cases, Mobil 1 15W-50 has been a WELL PROVEN alternative. Special needs often dictate special oils...depending of how close you wish to fly at the edge. Some "race" oils are low on additives for long term protection...requiring oil changes with each track outing. On the other hand, a "truck oil"such as Mobil's Delvac 1 5w-40 has a good history in our Vipers under a variety of circumstances. There are some great euro oils out there if money is no object. Oh, by the way, don't forget the "lucky charm effect" with special botique oils. I seriously doubt that there are very many Viper owners that have the amount of used oil analyses on Vipers that I have...dozens and dozens...from low to high mileage, street or track, and of course a few samples from folks who change the oil religiously every 4 years regardless of driving utilization.
I have been switching our Gen I, II, early Gen III Vipers away from the Mobil 1 10W-30 oils to Mobil 1. 0W-40 as recommend a couple of years ago by a prominent Viper engineer...especially since the synthetic 10W-30 ALWAYS tested a little low on viscosity...even with ****** oil samples sent from new quarts(also noted by Porsche) over 10 years ago.
All of that aside, make your own choices based on need, availability, price, and frequency of service interval that you plan.
Manufacturers of cars and oils have had to favor lower emissions and higher fuel mileage due to regulation. Sadly, this switch does not necessarily favor engine longevity and durability in my opinion. You would be appalled at the state of the oil sampled from late model Mercedes and BMW's when sampled at the dashboard-indicated service intervals. My lawnmower oil has better looking oil than seen in some of the examples...and, NO...I don't take great care of said mower.
P.S. You should pay close attention to brake and clutch fluids...as well as coolant to keep your Viper free of trouble !!