Finally got around to doing the BCS bypass and at the same time replace the vacuum lines. I didn't use silicon, but good quality Gates hose. I also left the old lines in place for easy re-connection if needed and because they were in pretty good condition.
Test drive was positive, but not able to fully explore the difference as we are having a wet day in Melbourne and traction is a bit dicey. Also the crappy Roadstone front tyres that have been on the car since I bought it, don't like the wet.
All and seems smooth enough.
Also replaced the lines off the Turbo and front BCS.