the hot shot requires a full jug when first tried then no more than a quart with oil change. Seems to work well I have 04 6.0 and it runs fine. Additives are recommended for fuel for the 'dont use additives' guys since the ULSD does not provide the lubrication that the old diesel did. Hot shot and others like amsoil all offer fuel additives its just up to the individual on what he does. I put diesel kleen in at fillups the grey jug variety. Ford also sells their particular brand of fule,additive dont know about the rest.
