Micko is saying the "chocking turbines can't cope" and is restrictive, if that's the case it doesn't bother the z32 setup.
The heat Simons setup saw would definitely be contributed to the factory inlets on a RB.
Biggest exhaust in the world won't help with a smaller intake,
That's the reason race cars and bikes run there race class restrictor on the intake side.
Simon told me he also had a 3.5 exhaust which chokes the system at HIS power level generating unnecessary heat.
My Z32 had twin 3" straight through with big intakes.