I fitted the booster plug, it did make for a better throttle response and an smoother ride and reduced the decal popping a bit, but on the downside when I came to do a major service I noticed that the plugs were fouled, I also removed the throttle bodies to give them a good clean and the back of the inlet valves were covered with black tar carbon. I removed the booster plug and a few thousand miles later checked, plugs normal most of tar gone and better fuel economy by about 10 mpg. Hope this helps.