Fourth Tier Psi Powers
Antipersonnel Pistol Rounds Fourth Tier Neural Capacity (50 Cyber Modules)
Description: Enables fourth-tier Psi Powers and raises Psi Points by 8. All fourth-tier Psi Powers cost 4 Psi Points to use.
Assessment: There are some good fourth-tier abilities. The real question is how dedicated you are to your Psi play-style and how much you're willing to rely on non-violent and alternative tactics. This tier is sufficiently expensive to purchase that it's not recommended to all but the most psychic of psychics.

Antipersonnel Pistol Rounds Photonic Redirection (12 Cyber Modules)
Description: Renders you invisible to all creatures. Firing a weapon ends the effect. Duration: 5 seconds + 5 seconds per Psi.
Assessment: Far and away one of the most useful Psi abilities. Not only is this one extremely useful for avoiding strong enemies, it also becomes very effective on the offensive when combined with Localized Pyrokinesis. Additionally, it's possible to sneak past some of the hardest fights in the entire game, right up until the very end.

Antipersonnel Pistol Rounds Remote Pattern Detection (12 Cyber Modules)
Description: Shows the location of useful items, including Nanites, ammo, Hypos, Implants and Audio Logs. Duration: 1 minute per Psi level.
Assessment: You have eyes, so use them (no offense intended to those with impaired vision)! The only time this skill might be useful is in dark corridors and when searching for hidden items, but even so, you may as well just increase the game's brightness if you're having trouble finding things. As a first-tier ability it might have had some merit, but considering the cost, this one is just not worth the Cyber Modules.

Antipersonnel Pistol Rounds Electron Suppression (12 Cyber Modules)
Description: Immobilises any robotic target. Duration: 3 seconds per Psi level.
Assessment: Only effective on robotic enemies, and more expensive than Psionic Hypnogenesis. The low duration is a major sore spot, but when used as a combat ability, it can render those powerful Military Bots useless while you tear them up. However, as a pure Psi user would probably want to bypass the stronger enemies rather than fight them head-on, it's questionable whether this ability is worth using, considering Photonic Redirection works just as well to evade robots. Only get this if you plan on augmenting your Psi Powers with weapons.

Antipersonnel Pistol Rounds Psychogenic Endurance (12 Cyber Modules)
Description: Increases your Endurance by 2. Duration: 2 minutes + 1 minute per Psi level.
Assessment: Endurance is not a major concern except at high difficulties, when Hit Points are extremely limited. Even so, probably not worth the cost in Psi; you're better off using an EndurBoost(TM) Implant, or just spending the Cyber Modules to improve Endurance.

Antipersonnel Pistol Rounds Molecular Transmutation (12 Cyber Modules)
Description: Turns ammo and Hypos into Nanites.
Assessment: By the time you can afford this Psi Power, you'll have the Recycler. The Recycler does, admittedly, require one inventory slot, but it's unlikely you can't spare one for it. I'm not sure if the earnings are any bigger using this skill, but either way, it's hard to justify this one.

Antipersonnel Pistol Rounds Remote Circuitry Manipulation (12 Cyber Modules)
Description: Allows you to hack from a distance. Uses half your Psi level (rounded up) in place of both Hacking skill and Cyber Affinity level, and costs Psi Points instead of Nanites.
Assessment: The major Achilles' heel of this skill is that it makes your Cyber Affinity and Hacking levels useless, meaning that not only are you in effect required to use a third attribute to hack, but it's not very useful except on lower-level objects, like Turrets. That said, hacking from a distance definitely has its uses, so it's not a bad choice... so long as you don't go trying to hack high-level security crates with it.

Antipersonnel Pistol Rounds Cerebro-Energetic Extension (12 Cyber Modules)
Description: Turns your Psi-Amp into a powerful melee weapon. Duration: 10 seconds per Psi level.
Assessment: The weapon you get is second only to the Crystal Shard in terms of raw damage output, but doesn't require an investment in Exotic weapons or Research. Combined with Adrenaline Overproduction, this becomes an extremely effective way to take down the tough enemies like Rumblers. As a pure Psi user, you'll almost certainly need to rely on this combo in a few situations. Most others can ignore this.