Just take the turbo off mate make it na then your r34 will be faster than the falc just hollow out the turbo with a hole saw then it wont be a restriction it will be cheap as.Or sell the skyline and use funds to buy an atomic bottom end and big turbo.
No extra power just more heat and detonation mate.The small turbo is maxed out in air flow at 320rwk or so it just can't push any more air efficiently and it just cooks the air time for a bigger turbo or e85