The effects of heat soak on some open filter cold air intakes can be substantial as they tend to be installed inside or near the engine compartment. While they promise a 3% or 4% performance gain when cold, there is a 1% decrease in HP for every 10 degrees of intake air temp rises. A realistic 30-degree temperature rise from the engine compartment can easily erase these gains.
The best intakes get their air directly from the outside and are often just improvements to the factory designs. They are larger and typically have smoother internals to help increase flow. These types of intakes tend to be more expensive than the open filter designs.
Often buyers just crave for the Induction sound rather than just pure performance. Open filter performance intakes readily pass through induction noise which can be intoxicating in the cabin. I am not sure how the factory style intakes do with induction noise, but I’m sure there is some improvement.