Read some reviews that the D05 is dead out of package
I get why some players would say this. It is a relatively hard sponge and if you don't generate the racket speed required to really get into that sponge then it's gonna feel dead vs (for example) T19 or Rakza 7.
and need some boosting to show it's true characteristic
It doesn't need boosting to show it's true character.
However, if you don't have the power or technique to really use the rubber then boosting will help you by making it easier to get speed and spin from a D05.
However, booster will obviously
alter the rubbers characteristics, so you no longer have the rubbers true characteristics. Makes sense?
To really get to the rubbers true characteristics you need to be a very good player.
Below a certain level this rubber is just a waste of money.
If you have to ask these questions then honestly, D05 is not the rubber for you.
Try the Glayzer, half the price, same long lasting topsheet, more performance for anyone under 2000 rating, different, and softer, sponge.
And absolutely no booster needed 😉