A few different reasons, the big one being that this kit was listed on the370z.com used for an amazing deal with the 928 motorsports impeller and the 9psi pulley.
I would have loved to get the GTM kit as I really like dealing with GTM as a company but the stage 1 just wasn’t enough power especially when coupled with a full exhaust. The stage 2 was better but still has the exact same power curve and seems to be almost the same exact power as I have now when taking into account GTMs seemingly very high reading dyno.