WE fitted it originally to overcome what we thought was a fueling problem with the Charger software.. turns out it was something completely different. Apparently it's best to tweak the valve on a set of rollers. It basically just increases/decreases the fuel pressure with the turn of a screw. You could definately make a difference to the running of the block, but again it really needs to be set-up on a set of rollers to get the optimum setting. As you can see, I've still got a few bits and pieces to be fitted this year, so once it's all in and I go and get it set up I'll be able to give a