If you are scared of messing up, I would recommend that you pick up some test cards with the same chips that you want to use in your implants (for example, the T557 test card for the xEM/LF part of the NeXT) from KSEC, or even their complete bundle. So if you do mess up, you only brick a 3$ test card, and not a shiny new expensive implant. You can also test if you were sucessful using the test card. Also keep in mind that there can be problems with coupling with implanted chips, so if I were you, I would look into the DIY LF antenna for the Proxmark3 Easy.
3 Likes