I was experiencing the infamous "Heat Soak" with my 2004 Jeep Wrangler TJ Rubicon, where the engine can get hot enough to vaporize the fuel in the fuel rail and fuel injectors resulting in a rough idle and misfiring of the engine after a "hot" start. I did some research and found a solution made by Design Engineering that replaces the usually worn out, factory heat shield above the intake manifold and also adds heat shielding that wraps around the fuel rail as well as the fuel injectors themselves. The kit also comes with new o-rings for the fuel injectors and I figured if I was going to have to take those out to replace the o-rings, I might as well take the opportunity to upgrade the fuel injectors and I chose to go with a set of refurbished, Bosch 7-hole fuel injectors that I found on ebay. The added holes these injectors have over the single one that the factory comes with, should create better atomization of the fuel, resulting in increased fuel economy, acceleration and, at the very least, result in a smoother running engine. Although by doing this install myself, I learned the hard way that the injector o-rings must be lubed correctly or they will not seat properly in the fuel rail, resulting in leaking gasoline from the fuel rail and the injectors, which made a huge mess!