1. bushings
2. motor/diff mounts
3. wheels/tires
4. coilovers
5. suspension arms/bushings

should increase your performance more than any meaningless intakes.

With a 2019 model, i dont see the need to upgrade subframe bushings and mounts, theyre fine for now

Maybe a stupid question, but what sort of improvement or change do you see when changing motor/diff mounts or subframe bushings?

Handling improvement. All other things being equal, you will have better transfer of power through the drivetrain with stiffer mounts and bushings. Rubber mounts dissipate energy during chassis movement, providing more comfort.

IMO a drivers car is about getting the connection and latency down between the driver and the car.

Like a PRO GAMER... you want the latency between your actions and their results to be as fast as possible.

In addition you want the stimulus coming from the car (via the tires etc) to be transmitted to you as quickly and accurately as possible.

The problem with the Z imo from stock is there is considerable delay from when you give the car inputs to when they take affect.

Like throttle input takes half a second before the car does anything.

This is partly due to the ECU, which can be fixed via a tune.
And partly due to flexible bushings and mounts.

When you apply throttle, the engine flexes in its mounts first before delivering the torque to the drive shaft.

Then the diff flexes in its rubber bushings before delivering torque to the axles.

Stiffening up the bushings really reduces the latency between your input and the car actually doing what you told it to.

https://youtu.be/9YyDH1-BR5o?t=976

the gain in bushings is most realized when going from shitty worn bushings to stiffer new ones

brand new stock to upgraded bushings is a minimal improvement that i would table for much later

he isn't some race car driver out to get every fraction of a second, so his dollars are better spent on . . . .a coilover and adjustable arms

bushing replacement is also a labor intensive job. You're dropping a subframe and removing bushings, possibly with fire (yay!)

A brand new Z with the sickest, upgradiest bushings STILL won't have front camber adjustment or height adjustment, for example

Fixing the much more obvious and impactful flaws is a higher priority than something in the margins

This is like being served a really shitty steak dinner. A prettier table mat might make the experience slightly better, but . . . you've still got a shitty steak dinner.