Just some suggested edits and clean up. I like tin man a lot, but I think it lacked a little bit of punch for an 8th level ability. The class requirements were also a little low. I'm not sure the core ability actually works in its current form unless the version of cyberware you are working with allows a Chrome higher than 10 (it's a table that stops at ten for the version I'm used to). The Spell Defense was too low to make a difference in its previous form.
You thrive out past the edge where metal meets flesh.
Requirements: Con 13+, Wis 15+, Upgraded
Class Skills: Athletics, Computers, Drive, Electronics, Mechanics, Medicine, Notice, Profession, & Resolve
Skill Points per Level: 4 + Int modifier
Vitality: 1d12 + Con modifier
Machine Driven: Your maximum Chrome rating is set to 10 plus your Starting Action Dice.
Body of Steel: At Level 1, you gain +1 Chrome. You also add your Class Level to your Cyber Threshold.
Less than Zero I: As you become more machine than man, you start to lose yourself within the machine. At Level 2, you gain Contagion, Stress, and Subdual Resistance 4. You are immune to Constitution damage and the bleeding condition. However, you gain the Burden of Ages NPC Quality
Less than Zero II: At Level 7, your Contagion, Stress, and Subdual Resistance increases to 8. You are immune to the sickened, stunned and paralyzed conditions. However, you no longer heal naturally.
Metal Diver: At Level 3, 5, 7 and 9, you gain +1 Chrome or an additional Gear Feat.
More than Machine: At Level 4 you gain the More than Machine feat.
Outside Yourself: At Level 4, you gain Spell Defense equal to your Constitution score + Chrome. Further, you gain the astral awareness NPC quality.
Rugged: At Level 6 your constitution score increases by 2.
Full Borg Conversion: At Level 8 you gain the Full Borg Conversion feat.
Tin Man: At Level 8, add you Chrome to your maximum Wounds and Vitality.
Ghost in the Shell: At Level 10 you gain the Ghost in the Shell feat and no longer have a Cyber Threshold.
Gear: Medium (GWS)