Sealants are silicone, not silicon. "Silicones, also known as polysiloxanes, are polymers that include any inert, synthetic compound made up of repeating units of siloxane, which is a chain of alternating silicon atoms and oxygen atoms, frequently combined with carbon and/or hydrogen. "
You'd be better off with a 0w40 with the engine being that hard on a 30 grade, especially since its turbo-charged. I wouldn't bother with half 5w30 half 0w40, go with mobil 0w40. It has a viscosity of 12.9 CST @ 100c, which is just above the max viscosity of a 30 grade (12.5 cst). Should shear down to a mid-30 grade with how hard that engine churns the oil.