To me the OEM springs and shocks are just enough for what they have to do, hold a stock vehicle up.
IMHO… you need heavier spring and shock to handle the extra weight of the plow and frame work.
See if there is a variable rate coil spring to fit your needs and extra weight.
I know when you add an HD Front bumper and winch the front coils start to **** after a while so think on it, figure out the added weight and contact a spring company.
Also get their suggestion on the correct shocks to use with their springs.
4x4, 5sp, Std Cab, Stepside, E4 Red
4” Lift - Coil-Overs, 6” SkyJacker Leafs - No Blocks (Mistake)
31 Spline FX4 Rear Axle, 4.56s and OX Locker, Hurst Shifter w/Optional Stick and "Made by Grev" alignment adapter