vr6squareback28

I work at a machine shop and bought a core 12 valve vr6 engine code AAA. Came with nothing but a coil pack. I’m putting it in a 1973 VW Type 3 Squareback. It of course will be turboed and I am trying to figure out if OBD1 or OBD2 is the best option aftermarket wise and also easier depending on pros and cons. I have had a 2000 GTI GLX with this same motor in it but wasn’t into this stuff at the time so the most I had into it was exhaust and suspension and didn’t really need to think about this. Any help I can get would be great.