I used Bestline’s Fuel Conditioner and Catalyst when I needed to fill up on gas and decided to run Shadow on the highway to let it work in. After about a week I noticed she picks up a little quicker on the highway and my mileage has gotten slightly better which definitely helps out when driving a V8! After this I mixed in the Engine Treatment with my new oil when the time came around for an oil change. Along with a higher quality oil and adding the Engine Treatment she sounds better, idles smoother, and it feels like she’s even gotten a few years back along with the power! Bestline is a product I can see myself using for years and I have CarSponsors.com to thank for introducing me.