Should I D rate my power distributor for exploration ?

I see that a lot of explorers d rate their power distributor, often a 3D and choose to have insufficient power but huge ly jump. Does that mean they will need to manage module power in a certain way ? Because I can’t imagine flying out in a ship that has not enough power.

Also, I chose to a rate my power distributor so I can permaboost while flying. I’m at 67 ly jump, but I still wanna squeeze a few ly more. What modules should I engineer ? I engineered my fsd to the max but what other modules should I engineer ?