in additioin to the other upgrades installed
The Jet Power-flow spacer has helped the other engine upgrades that I have installed. These include a PCM of NC performance PCM, Jet Power MASS sensor and a Volant Cold air intake that connects directly to the throttle body. I'm not sure of the total HP/ torque increase, but this upgrades have made the 4.2L perform like a V-8 and has given a consistent 20MPG on the highway (highest was 23MPG on the highway) which is better than the 17MPG that I was getting in stock form.
This is my second Volant intake, and I will keep buying them! There was a noticeable increase in intake noise from half to full throttle, which is normal and sounds great. The fit is a little tight. I actually had to rotate the filter bellow so that it would fit in the air box. Other than that, it fit great. I did add a tuner after the intake and it really woke up the engine.
Easy to follow instructions, can hear the difference when I press on the go fast pedal. Would have liked to have the rubber gaskets precut vs. having to cut them. The intake definitely frees up some of the space under the engine cover very straight forward unlike the stock intake that has wasted space.