I am not aware of any hi-po mods for the "E" series DT466. The days of adding some fuel with a screwdriver are long gone... Depending on the HP rating of your engine their may be some different programming available from the dealer, but that is a real long shot. In the meantime, make sure the engine is running as it should. e.g. Proper amount of boost, correct fuel pressure, etc.
A different approach would be to start planning a 3406 or N14 swap.