When tuning down to drop d and below, do you need to make any adjustments to your guitar i.e neck bow etc.? Or at least drop d? Also, will you get used to the notes change when tuning to drop d, and what is easier to play in this tuning than standard (like do chords become easier)?
well chords are different, so your open and barre chords on the E string all change slightly. you don't tend to need to adjust anything, except getting thicker strings. get at least 11's IMO.
If your guitar is nicely intonated already, drop d tuning shouldn't be a problem. May get a little pitch difference when drop tuning your E string to hell. Also depends on what gauge strings you're using. Tho if you're drop tuning all your strings then yes you may get some out of tune notes the further you play up the fret board.
some power chords get easier and i think it would be smart to buy some thicker strings