well, its not. i just needed the body lift when i did the cummins swap to cram the huge radiator and air to air after cooler. Kinda like they did with the M35-A3's with the cats, only they didnt lift the cab they just lifted the front of the hood and let it be at an incline UP in the front. Although i do think it is very helpful to have the 3 inch tube on the bottom because the roof dosent realy add any structure like a car would and it will now be twice as long, making it prone to a bow in the center unless it is supported in the middle to the frame. Then you run into flex problem under high articulation.
"real trucks dont have spark plugs"----thats awsome, wish i had thought of it