I've had this spacer for years. Running 30 pounds and consistently in high Rpms during racing I notice about a 30 degree difference with a infrared temp gun pointed on the intake manifold after installing. My iats stayed more consistent as I made multiple laps around the track. What I enjoy most about this spacer is after parking I don't have to worry about using ice bags to cool down my intake manifold so I'm ready for the next heat. Great product Period.