I used Bosch platinum plugs a long time ago, that did well. But in my opinion, over the years, I use only Autolite double platinum plugs.
They last a very long time. I do not lok forward to changing them on either of my 3800 engines. On my GTX, I use 3 heat ranges colder. They still last, even when blasted by a 150HP nitrous shot multiple times. Just my experience. Good Luck...
