What does more for a car's performance(HP & Torque): Cold air intake or a performance exhaust?

In the real world, neither will improve torque and only the exhaust would have a chance of producing a noticeable change in power... and even that would be small, at the higher rpms. Many cars, especially Toyotas, suffer power loss with an aftermarket intake.

HP; torque is more of an issue with heavy load taxing like amps are to electricity, and HP is more like the voltage pushing electrons in electricity. That's the easiest way to correlate the difference between the two power factors. The breath ability is only a sliver factor in increasing power, that's where the turbocharger fills in to get the boost. Adding a hotter camshaft is where you will get the major increase in power, the fine line between durability and destruction.

There is no one single answer that applies to all vehicles.

Secondly, if either of those components is badly designed, they can actually rob a vehicle of performance, not help increase it.

Headers and a free flow exhaust.

Hi none of the above a high lift camshaft would change things. with a gas flowed head.