I get a better result with 20 grams brewed at 85C (with preheating) than at 95~100C with/without preheating.
I've seen many passionate arguments about temperature, and oftentimes people regurgitate what someone else has written in an online forum, and they keep repeating something like a gospel. Whereas, in practice, things often vary from bean to bean. Different beans often require a different recipe.
Also, if you are sensitive to caffeine, lowering the temp can really help you stay productive without the overwhelming hyper-stimulation. You can get tasty cups at lower temps too. In fact there's been a study on this. People couldn't distinguish shots brewed at 88C from shots brewed at 93~95C (I don't remember the exact range). One more benefit of the lower temp is that people avoid burns.
Hence, 100C is not some gospel temp. It doesn't always produce superior results. [at least in my experience]
Some details:
I mostly do turbo shots.
Primarily medium-roast beans.
I practice slow-feeding.
I preheat only the basket and the top screen.