Total nonsense. Valve size has little to do with torque. Some day, all these wives tales will die off. I hope.
So to tip everyone over, I could make the argument that a 1.600 exhaust valve is too big. My next W2's are getting 1.500 exhaust valves. Most people who port know that a smaller valve with a 92-95% bowl makes more power.
If you ar not willing to pay someone to do the work, use a 2.02/1.60 valve package, get the bowls correct and let it alone.
Some things are counter intuitive and exhaust valve size is one of them.