There aren't any standalone units that I'm aware of, that work with an OBD-II ECM, at least not the way Hondata works with the OBD-I ones. You can go with another unit like AEM EMS or Power FC, etc, and those will plug right in and work with OBD-II, but they replace the ECM altogether. Pretty much any standalone is going to cos a significant amount of money.

With a standalone, there is no need for a boost dependent FMU since you'll most likely use the standalone unit to control larger injectors that will handle your fueling needs. You don't need an AFC because you the standalone to control your fuel map.