it depends on how much of it you want to take off.

the front part of the pulley will come off with 6 10mm bolts but the other two pulleys in there you have to take out the crank bolt. i believe its a 27 mm. idk much about using impact guns but i know a breker bar with maybe a lead pipe extension should get it off for you. thats what i used.

and no, theyre not opposite threaded