Cheers Ian,
Edit: Updated my post. Read your message again, in detail.
I believe that the friction created in the IC tubes, together with the rubber expansion, will have minimal impact on the boost pressure... if even measurable. (I'd be happy if someone can prove me wrong here!). Please note: prove me wrong on OUR cars. I know other cars have issues with pressure drops that can be remedied. But remember we have (relatively) large ID tubes, and they are (relatively) short as we have 2 SMICs close to the turbos instead of TMIC or FMIC - which require a lot more tubing, often with bends building up additional friction.
When it comes to the temperature - yes certainly silicone has very low thermal condictivity - meaning that the charge air will be (slightly, possibly measurable) cooler than with stock rubber tubes - which is good.
I'd love to hear a sales pitch from the manufacturer, hopefully backed up with some data. (Which in the end could possibly motivate me to purchase these tubes... which are.... quite... expensive.... thb...

)
Edit: What I'm saying is this: There is absolutely nothing wrong with these tubes - they will improve your car's performance. But how much/little? A brief cost/benefit analysis, for me, today, tells me it's not worth it.
I'd love to be proven wrong.
Hello from Sweden/Philippines.
My IKEA geschwindigkeitwagen! (766 hp / 571 kW / 1051 Nm), MRC'd, 22" forged, 'ramix, Milltek, ILR carbon bits, MTM adjustable springs.