So I've got some steelies comin for the winter and am wondering if I absolutely need an install kit with these wheels. I know I'll probably have to retorque them a couple of times though. Thanks

Install kit? Like new lug bolts? Bearing caps? Valvestems? A torque wrench is something you should own.

You need nothing additional. Your lug bolts will work & steel wheels don't need centering rings. Bolt them on check the torque, adjust the air pressure & you're good to go.