First off, our spacers are waterjetted and machined pieces of Garolite G10/XX phenolic material, offering thermal barrier protection of the upper intake manifold from heat transmitted to it from the lower intake manifold (and thereby the rest of the engine itself). Inserting a thermal barrier here is a tried and true way of reducing the temperature of the intake air charge, improving power efficiency. The spacers themselves come in a 3/8 inch thickness for a strong balance between thermal functionality and increased port runner length, while still able to fit without hood clearance issues on most vehicles. (WE NEED TO VERIFY THIS ON AN S12, HOWEVER - SEE BELOW FOR MORE DETAILS!) Also, these spacers are designed to eliminate the use of a plenum gasket, and comes with silicone adhesive included with your purchase.
Our kits also include longer replacement socket head cap screws for those using a stock plenum (customers who have purchased an ASCO Gutted Plenum can simply reuse your stock length screws), silicone adhesive, coolant passage hose and clamps, and paper instructions, as well as a free Acadiana Sports Car Orphanage bumper sticker.
We are also pleased to offer a specialized spacer kit for Pathfinder and Xterra owners who have log-style upper intakes on their VG30 and VG33 powered vehicles. The Pathy/Xterra kit comes with the appropriate bolts for those style manifolds. Z owners using a Pathfinder or Xterra upper intake will need to purchase the proper kit for proper fitment.
All kits are 73.95 with free shipping, and can be purchased directly from AllThingsZ at:
http://www.allthingsz.com/store
Choose Engine Performance > Intake Manifolds and Accessories > Intake Accessories

Due to the unavailabilty of a VG powered S12 nearby, we are looking for one tester to try this product out. Some of our immediate concerns involve the retention of the EGR (Z31/M30's require the EGR tube to be removed or modified, Xterra/Pathy simply require bending the EGR Tube), as well as hood clearance and intake manifold bolt length. Will offer a heavily discounted price to anyone willing to test one of these on their car, and provide us with some needed info.
Thanks!
-Zack