Safe to say most of the power is in the tune, yes. A tune doesn't radically alter the engines demands for air though, that's mostly driven by compression, chamber and cylinder head design, cam timing and manifolding so, a large air tube in front of the throttle plate likely contributes very little, even in a tune-required situation.
2014 Premium GT, SGM, Brembo, Auto, Tech, Comfort, etc. GT500s, Steeda UCA, VMP auto tune, 100 shot on BBR tune, best et: 11.38 at 120.85
2012 GT, Candy Red, Brembo, 3.73, Tech, Comfort, etc. Procal tune, Roush upper, UMI LCAs, Steeda red bracket, GT500s, 28X10X16 Hoosier slicks, best et: 11.91 at 115.23 RIP