Which derosa is stiffest? King, merak?

I think that Merak should be the stiffest DeRosa in current lineup, but I might be wrong. Merak is rather heavy for an top of the line alu frame. It is 1500g in meadium size without the fork, so I guess it is made with stifness in mind, not lightweight.
And from what I've seen on the net King is very stiff for an carbon frame, compact geometry special. I'm not sure is new King Xlight as stiff as original KIng was. Old King had alu lugs and the ne Xlight has carbon lugs. Xlight is also 100g lighter than original King was.