I prefer Black Silicone (16B) over the Ultra Black. But I have been using the Gray more here lately, depending on the application. I'm not a big fan of smearing that stuff all over everything. Just a touch on the rear seal and rear cap joints. A dab in the corners of the pan gasket, end seal joints. The ends of the intake. Maybe a smear around the water passage areas of the timing cover if it shows any corrosion damage. That's it.