ThanksAC use will rob maybe 5 HP depending on the source. No other power penalties that I'm aware of.
The weight could help or hinder... More weight = more traction, but on a slope that weight above COG is a liability.
The Kioti CX2510 CAB is in the compact class but only 24.5hp.for sub compacts 30hp or below, maybe, but on yours (50hp?) think the added weight would only help, esp on ground engagement implements.
personally, i can't imagine a cab on sub compacts, but guess it does serve a purpose for those putzing around in the cold. regards