When we get caught up from the big sale this weekend we'll list the Z1 VQ37 intake manifold for sale separately and post more information and test results. For now here are a couple different dyno comparisons that were already on our server.
Completely stock Z34 vs Z34 with Z1 400HP package
Back to back dyno runs swapping intake plenums only. Car is making a bit less than 340RWHP because it has high flow cats and an Injen Intake as opposed to test pipes and a Stillen Gen 3.