Cork is original equipment for the automatic transmission pan but as you've said, FIPG - Toyota's part, is the recommended sealant for the oil pan. This is the first I've heard it would be less durable than cork. The first time I tried installing the pan, I was overly conscious of the time limit for placement and did smear it. Had to wipe off the freshly applied material and reapply. In the process of removing the material from the oil pan I sliced my finger. Being dedicated - my only concern was whether the bleeding would slow me down. It didn't. I realize this all sounds like an advertisement for cork preformed, but I really appreciate the continuing engineering improvements in the Toyota, and always stay with the factory recommended procedures and products - so if you use sealant, I would not be substituting for the Toyota part. I developed a slight leak in the coolant recovery tank from abrasion against the mounting bracket. Tried using RTV silicone for repair and it failed soon afterward. Tried FIPG material and it is still holding strong with no sign of degradation. That is also the only material I use at the four points on the valve cover gasket. BTW, standard silicone seal with acetic acid curing agent can damage the oxygen sensor when fumes enter the port open to atmosphere. My understanding was that FIPG on the oil pan can last apx. 10 yrs. I made sure the sealing surfaces were antiseptically clean and the materials were applied in the specified time. Everything looks very solid. I understand the most critical area is to apply the bead very close to the rear edge around the area of the rear main seal to avoid leakage in that area. The FSM has a diagram and I think Haynes also, but the idea is just to go close to the edge in the back side of the pan.