Is there any chance that we could change what stats the Psi lab alters? this way we could make gene splicing labs for our soldiers 
With what modding offers atm in terms of facilities it is currently not possible. Warboy1982's OpenXcom War mod apparently has some custom facility tags that aren't in the main OpenXcom release so you might be able to do it in that.
- Enhanced muscle strands
- Aquatic breathing - Gills (Man From Atlantis)
- Laser Eyes
- Claws
- Cheetah legs - more movement points
- Crocodile skin - natural armor
- Rocket Tongue - hardened chameleon tongue - A'la ALIENS - that can be shoot out once during a turn AP FREE so if a soldier fatally damaged an alien, but it didn't die, try to hit it with your Rocket Tongue in the face/eye to bring it down. Does 1 HP or minimal HP damage.
- Firestarter - Psychokinesis: soldier can explode into a fireball, aka Charlie in Firestarter. Causing flames to be emitted from his body, but the soldier is unhirt of course. A'la superman in Man of Steel. Later when a Firestarter is sent to a PSI LAB, this unique soldier can learn a skill, to shoot a "Fire-Mask" from his face - essentially an Incendiary Rocket - but more like Charlie shooting a Fire-Mask in the movie Firestarter.
I think the topic starter was suggesting making training rooms for stats, not for special abilities.
