Its about that time again, time for me to change my oil. But I was wondering if maybe I should go synthetic this time. I've got a 1996 3.5L, and it has 83,500 miles on it. Would changing to synthetic at this point make a profound difference? Or would I be better off staying with the high end petroleum based oils? And if I do change to synthetic, does anyone have instructions on how to switch over...or link stating how to do so? Thanks for any help.