The advantage of E-Manage over the APEXi VAFC/SAFC Neo is that it has ignition mapping while these APEXi only have fuel mapping adjustment, so in terms of making more power the E-Manage should be better. But the APEXi can have different fuel maps settings where you can switch between them, for example if you want to go for max power or more fuel economy. The APEXi also can be adjusted directly on the unit itself with nice displays while the E-Manage must be plugged to a laptop.