Been wanting a piggy back or ems. Found a emanage ultimate new for cheap. How hard is it to install and do I need a map sensor? €And is there anything else I need?

Just found a place that has pnp harnesses for the emanage ultimate. I have a jdm st185 ecu and engine The harness I found is for a usdm 1990-1993 alltrac will this fit my ecu? And also there was a few options with the harness with wate air sensor and knock sensor ect which do I need

i've read about quite a few guys having a problem with the emanage, and the 3sgte.