hondata is a standalone that uses the factory ECU. It's not a piggy back. the def. of a piggy back is something that gets in the way and feeds the ECU a flase signal. Hondata works the other way- the sensor goes to the ecu, and then out to the hondata.
NOTHING will ever start your car like the oem ecu will.
1000's pf people have problems with the aem ems. its just too advanced for its own good, and in my opinion, not designed for a street car. At that point, i'd go to speed pro anyway
and FYI
stage 4 is out of date by about a year now. s200 has replaced it.