For ESS supercharged E9X M3s that need to run a boost gauge or water/methanol injection, these Awron Velocity Stacks are the perfect solution. Each Velocity Stack is CNC machined from aircraft grade aluminum and tapped with 10x1.0mm and 12x1.5" ports for Awron gauge or water/methanol injection systems. Specifically designed to work with ESS superchargers, these Velocity Stacks can replace one or all eight of the original ESS units. Threaded plugs are included to block of either of the holes if desired. Learn More