I'd think that using 2 AE diff gaskets would create the same problem as using the Mugens...

I found out the hard way these last 2 weekends racing that the Mugen diff gaskets are not the answer... I've had to replace about 4 sets of spider gears because of them.

Like has been stated.. Just sand the diff cups till all the shiny spots are gone on the face of the cup, and use a stock AE gasket.