I once bought one of the silicone vacuum line sets they sold in the auto parts store to replace the vacuum tubes on my VW Golf. I noticed once I got home and opened the package that they are "intended for off road vehicle use only" but decided to use them anyways. I mean of all the times I had ever prior to that and have after that, not once has a officer asked me to pop the hood. My experience? If you want to use silicone vacuum lines DO NOT buy the kit like this.
They are not thick enough walled. The vacuum when applied to them will eventually collapse them. You need to get thicker walled silicone tubing if you want to go silicone. I was wondering why my Golf was running so bad and my gas mileage had dropped off so much until I popped the hood while it was running and found over half the silicone tubing collapsed.