Aground

So after completing the two mirrows quests that you get in new haven, (see the Human Testing achievement) you can then return to their lab and near the console you have the option to do "surgery". All you have to do is build the 4 items: Cyborg Eye, Cyborg Body, Cyborg backpack, and the Machine Gun arm. (sorry if those are the exact names but it isn't hard to figure out.) If you JUST want to get the achievement simply go save your game and then come back and build all of these and then reload. The Cyborg Eye is awesome, but if you want to use the spirit goggles you have to remove it (which destroys it) and then if you want to use it again you will then have to re-build/install it. The Mecha Wyrm Helmet is a good alternative that is removable, it doesn't light up as big of a circle as the cyborg eye, but you can remove it and it shoots a laser so acts as an added weapon. So pros/cons you choose.
Since I am going hybrid science/magic it works better for me.