Nimble Fingers is located in the Sub-Sewers beneath Freedom city. You cannot reach the mutation site without first defeating the bug queen. So long as you're over 5k XP and don't have a terrible build, you shouldn't have any trouble beating her, but be ready for her special attack! You must also kill/run past the many arachnos that live in the Sub-Sewers.
This mutation grants:
- +2 Reflexes. Reflexes is an extremely important stat. This translates to +1 dodge and (for many but not all builds) +1 to your weapon skill, and contributes to melee weapon speed.
- Direct buffs to brainy skills. This is a no-brainer buff for brainy characters. Also helps combat characters craft planes endgame.
- Gives the ability to Empath. Massaging someone destresses them, and also gives medic IP. This is mostly a flavor thing; if you've got time to massage, you've got time to use scrimshaws, which are way better. without a massage table or getting
- Negative 2-4 beat soak is a real kick in the teeth. Beat is a very common and very nasty damtype. You'll also shit your pants every time you see a junker. Many nimble-fingered players take High Density to offset this.
- -2 Endurance. Endurance is a really strong stat. This reduces your ability to use drugs safely, use focus, and resist everything from radiation poisoning to knockouts. This also means it's a contentious pick for Fists and Spears; the former will lose a point of skill and the latter will get a zero net gain, though both will find it easier to speedcap their weapons.
- Can't take Ripper. Only fists min-maxers care about this, and even some of them shy away because of Ripper's poor cost-benefit ratio. This also means that Nimble Fingers is incompatible with Abomination, but that mutation's even less popular than Ripper, so nobody really cares.