with the cost of feul these days, adding anything extra is going to push the costs through the roof....IMHO. Honestly, other tha "fred's hair tonic" aka Stadyne lubricity additive, just about everything else is money down the drain. many years ago when I first bought my truck, I added the Redline cetane booster religously. Problem was with fillups as often as I did with a commercial vehicle, the $35/gal for a questionable improvement, didn't make much sense. Hence, I've given up spiking my feul. Face it, CA feul is going to suck. Just learn to live with it. Unfortunately.