is this ok ?

well i just got done installing my dvd player and my 7" screen, im hooking up a switch to kill all the power when not in use but weill it be ok to grab it from the red wire under the stearing colum ?

anytime running a separate monitor or any aux. units always tap into the remote wire on the harness, you can trust that wire, that way it shuts off when the car is not on, its alot easier than running a kill switch you should never have to do that....

do you want to be able to control it independently so that it's not always on with the vehicle or radio? If that's the case I would just pick it up at a 12volt power supply wether that be behind the radio or under the column. Don't go buy wire colors, factory colors don't match standards, they have their own.