View: https://youtu.be/Uzju3xBFHaY
2-3 peak horsepower there, others reveal similar on the dyno. No, TB spacers aren't worth the money.
The problem is, you're trying to tune intake runner length on a plastic composite intake that has very few compromises in it's design. This isn't the old 5.0 pushrod days were the limitations of the aluminum casting process and others meant their were compromises.
Another benefit from the past that is lost on the modern engine is heat isolation. On TBI and carbureted engines, a spacer reduced vapor lock, on MPFI engines, it's not really a problem, and if it does occur, a spacer that never sees fuel won't help.
Damn, I must be helping or something,
@RaggedGT is putting out the Bat-Signal for me!