I'm sure everyone who has been following the progression of the power of the gods has noticed something. M.D.C. levels go from about 1880 (Abrasax the Insatiable) to 8000 (Horsemen) to 16,000 (Set) to 80,000 (Marduk) to 250,000 (Apsu)! Well, I can't find a good way to update those horrifically weak demon lords, but I can update the Egyptian gods and Horsemen.
In the Rifts® Conversion Book Two: Pantheons of the Megaverse®, we learn that gods get 5 times the M.D.C. in areas where their worship or power source is prevalent; this puts gods at somewhere from 6,000-16,000 M.D.C. This fits exactly within the boundaries of most of the Egyptian gods. Thus, in areas where the Egyptian gods are worshipped (not in Rifts: Earth), the following stats are the new ones:
Set: 84,250 M.D.C.
Anubis: 62,250 M.D.C.
Apepi: 34,500 M.D.C. However, Apepi may be a special case; being a dragon, he may not be worshipped, and his infinite regenerative capacities make his 6,900 M.D.C. quite acceptable.
Amon: 52,365 M.D.C.
Anhur: 37,350. Armor is unchanged.
Ammit: 25,000. I'm not sure Ammit would receive the upgrade either; he is sort of a god-beast, not a god.
Bes: 30,000.
Ra: 70,000.
Thoth: 72,350 (or so he believes), actually 200,000; I would think that Thoth would receive the upgrade, as he is definitely a popular god, and he was an Old One. 200,000 M.D.C. appears to be actually low for an Old One. However, his transformation circle effect would appear to account for that.
Isis: 60,000.
Horus: 27,500. I do believe that Horus was worshipped, and the power of worship did likely up his power. However, his cousin Lyphan remains unchanged.
Bennu: 30,000. Considering her regenerative powers (including reincarnation almost as good as a Scarecrow or Apepi), this is not bad!
Apis: 32,500.
Sebek: 32,350; Sebek was always a weak chaosmaker.
In addition, if one were to fight the Horsemen in their own dimension, an option of a G.M. would be to have them permanently killed if they were killed there, but use the following stat modifications:
Death: 83,165 M.D.C.
Famine: 33,765.
Pestilence: 35,615.
War: 42,410.
Super-Creature: 180,000 M.D.C!