I have used Red Line for over 39 years. Great oil - I use their gear oil in most things. I Used Royal purple in my 430RWHP 13B - 93FD street car (2,805 LBS with driver) using 91 octane because it tolerated the heat better that the other oils early 2000. I used mobile 1 because of Costco Price in my street cars including my 2004 2RZ Toyota which is at 225,000 miles now with out a hiccup. I changed my oil for street cars every 2500 to 3500 miles when I rotate the tires and do maintenance. Unfortunately my Costco does not carry Mobil 1 any more so I switch to Amsoil - Great product but expensive. Oil is now changed every 5000 miles for my street cars.
Adding an oil stabilizer to any different brand of oil is not a good idea. Current synthetic oils are better than they have ever been. Don't dilute them with a brand that they were not designed to be used with. I use Driven Oil in all race applications. I can not recommend a better oil at this time.
VP gas additive is a recommendation also.
If you made it though this hole post - Free advise / internet is worth what you payed for.