There's no need for 'enhanced defense' (ed) mod on an eth armor, normal armors can be bugged as well. For 4 sockets armors, just make Stone runeword, then remove it with Hel + tp scroll in cube, repeat 1 more time, till base defense of the armor hits 2037, then make Fortitude. For 3 sockets armors, the process is the same, only the runeword is Duress and it may take one more repeat, again till it hits 2037 base def. At the end, make whatever runeword you wanted in the first place (the usual are Duress and Treachery). The final defense of the bugged armor comes from the '+xxx% ed' mod of the runeword. An example: say you made Fortitude, which gives +200% Enhanced Defense; this means that the armor will have 100% base defense + 200% from the rw, which is 300% final defense. If you followed the steps, the armor would have 2037 x 3 (this is the translation of 300% ed) = 6111 final defense. It could be a bit higher, as @Kefflar32 mentioned, if you use a superior eth armor that has some +ed, but the increase is fairly small. If you do not arrive to this number, you're doing something wrong.