Trickflow trackheat or performer rpm

The rpm most likely be better under 4000 rpms where your engine will live 98% of the time, but I'd still start with what you got and go from there, least when/if you go rpm you know exactly what's the difference and which you prefer. You might see no need for more than you got now and no need to spend more money.

Plus on a full throttle or even aggressive part throttle how much time are you gonna spend under 4000 rpm to benefit from the extra low?

And under normal driving your engine more than capable of making the 5-50hp it takes to move your car at regular driving speeds. Unless your intake lacks at various part throttle driving you might not notice to much difference between them.