Any additional components increase power draw.And will any other modifications (graphic card, bigger RAM and hard drive) make difference on selection of power supply????
If you replace the HDD with another one, the power draw will be about the same, so it's not too big a concern.
A video card can increase your power draw dramatically, depending on what you use.
There's no need for high-end 3D graphics in the car, so going with on-board graphics is generally recommended for the power draw.