from an engineering stand point, yes, in theory it does help reduce the conduction of heat from block to intake manifold. However, you won't get much benefit from it since the engine bay will reach a more homogeneous temperature over time assuming steady-state.You know, for spacing your phenols. 2017+ Elantra Sport 1.6 Turbo Phenolic Intake Spacer - Shark Racing I like the part about installation being "very easy," though I'm less enthusiastic about the "experienced mechanic" part.
I had one on my turbo Miata and it came with dyno proven gains. But a Miata intake manifold is aluminum, ours are already plastic, so I don't see it having any positive effect.As for the heat..."will substantially lower the temperature of the intake manifold, resulting in more power." sounds like pure BS, especially in the absence of data to back up the claims.