You can get an engine with basic mods to work pretty well by remapping the standard ECU - its works well for mild modifications and supercharging.
I wouldn't expect to gain a huge amount of power by swapping from standard to an aftermarket ECU on a standard ish engine, but we'll see.
The main benefit of Syvecs is all the other features - the standard ecu runs the engine quite well but thats it. With Syvecs you have full control over ignition timing, traction control, boost control, on board logging, safety engine limp / trips, nitrous control etc etc. And rather than having a load of separate systems controlling these things its all in one unit that is designed to work well. An example of this is traction control - you can set it up to initially just retard the ignition to reduce engine torque when wheel slip is detected. Another is the nitrous control - you don't need extra fuel injectors as the ECU just injects more fuel via the existing injectors when nitrous is on. Boost targets (if you have turbo engine) can be based on throttle position, gear and rpm. You can setup trips so if the fuel pressure fails to follow manifold pressure it'll either go into limp or stop the engine.
Probably over kill for a daily drive but extremely good for a modified car.