Good luck in your search!!
The main reason stock replacement Magnum heads are so readily available is……..factory ones are usually cracked.
Currently you can buy replacement Magnum bare heads for $482/pr with free shipping on ebag.
I don’t know how that compares with what you spent for the EQ’s…….and not that this means anything, but the ports don’t look as high on them in the pics as the EQ’s.