1. Advancing the ignition does not give you more power unless you are doing it to use a higher octane fuel in a petrol car.
2. Diesels until recently use auto ignition, which cannot be re-timed. Some of the high pressure injection engines inject the fuel at the point of firing/s, this could be altered, but there would be no advantage to pre-ignition.
Changing the injectors can increase bhp, I got 30bhp more.