The plenum volume and runner length combination has been selected for aggressive low and mid range torque while opening up power higher in the rev range. The plenum volume is large enough for serious gains but is still compatible with factory AC. The Street version is suitable for any level of performance modification as we have conducted tests on completely stock engine/turbo/fuel system setups with approximately 9% gains in torque and power level, with the same percentage gain on highly modified setups running E85. For a fully streetable but aggressive setup while retaining the comfort of AC, the Street version manifold is the solution. For cars requiring more power in the upper rev range the street version can be supplied with shorter billet TGV's (lower runner section).