Under a static load /RPM condition, raising the ignition timing while keeping all other factors equal (air charge temp, Fuel-air mixture ratio, Lambda reading steady, engine already engaged in closed-loop operation, etc.) may or may not increase the power output of your engine (this is because the ignition timing set in the factory already factored-in the flame propagation pattern/timing inside combustion chamber to obtain the most output while keeping the emission level within specs.
This is applicable to N/A engine with computerized EFI engine systems.
"tricking" A/F ratio with a little bit of ignition timing advancement (while keeping all other factors equal) generally resulted in a few % horsepower increase but since this is also partially controlled/compansated by computer engine management system, your gain would be small (because when engine sense a detonation signal due to excessive ignition timing advancement, it wll retard the ignition timing abit and/or throw the engine into "limp" mode so as to reduce any damage caused by detonation.
So, the bottomline is, in an EFI controlled closed-loop N/A gasoline engine system, stock ignition timing gives you the best overall performance while all things considered.
IMHO any silly tricks in altering the settings (ignition timing, A/F ratio, etc.), unless tested on a dyno, proves nothing.
Turbo/supercharged gasoline engines require additional analysis before any observable benefits can be achieved, esp. by merely advancing the ignition timing.
