Hmm. Which intake are you getting?
I thought the supposed "heat soak" issue was only said to be related to the '04-'05 Steeda Intake:
But you have an '04 youngkal, which means you will be using a different Steeda intake:
No matter, because both these intakes are of the SRI type design (Short Ram Intake), in that they do not pull in "cold" air from underneath the engine bay.
And the SRI design is said to lose 4-5 hp over an actual CAI (Cold Air Intake) designed intake.
Anyways, I've been using the '05-'06 version Steeda Intake on my '06 ST, and have not encountered any type of "stalling" or "stumbling" (and we just had one pretty hot summer).
That's my .02!