In the category: 'D&D monsters that never should have been'; the Achaierai. It's a horse-sized flightless evil bird that can release smoke that makes you insane. On the topic of insanity; what was TSR thinking when they came up with this thing? Did they get together and decide a magic smokebird would greatly improve the game?
6 racial hit dice aren't great. I guess one should be grateful they're at least outsider type, though. The skill list is pretty bad, and the spell resistance will be as annoying as it's useful (remember, there's plenty of SR:No attack spells, but few SR:No buffs). Achaierai have full BAB, strong natural attacks, Large size and a natural strength bonus, so they make natural melee combatants. The smoke attack is sub-par, though.
In the end, Achaierai aren't significantly stronger than a tier 3 of equal level. +0 LA is fine.