I would suggest just good whole peeled tomatoes, run through a food mill or gently pureed, with only a bit of salt. The sauce on a marinara is no more important than on a Margherita. On either, it's about the tomato not the "sauce."
I top a marianra with sauce, thinly sliced fresh garlic, fresh oregano, a tiny pinch of sea salt, and good evoo - maybe a leaf or two of basil - maybe a tiny pinch of dry oregano - maybe a pinch of red pepper flakes. I don't like any cheese on mine at all, but you might. Recently Willard (2stone) turned me onto using a lot more garlic and oregano than I did previously. It's kind of out of balance, but it's a good pie. A little swirl of Calabrian chili oil post bake is very good too.
My "typical" marinara: