Narco and Striking Calluses have already been mentioned (really great gear. Narco alone can obviate the need for many other expensive pieces of cyber-/bioware)
So I'd say: Retractable Climbing Claws
They are 100% legal but act as hand razors with -1 Limit (Physical limit can get ridiculously high with high strength, so this isn't really a problem)
If you take 4 (2 hands, 2 feet) you gain +4 Climbing Limit and +2 Climbing DP.
If your GM is reasonable, he'll also allow you to gain +1 Reach if you own a pair, since there really isn't any reasonable difference to bioware claws
There are also a few very nice qualities:
Biocompatibility is great - especially with used ware (1.25 Essence becomes 1.15),
Prototype Transhuman and Striking Callusses + a few grades of Bone Density Aug are a godsend for unarmed adepts
Revels in Murder is a borderline broken quality, making edge kills sustainable
Finally, superhuman psychosis is a neg. quality with lots of goodies for all those near cyber zombies