Talked to a seller on eBay before I did some of my silicone and here is what he said:
"All the normal silicone is actually resistant to oil vapors/mist, so it will work in the breather system, if a build up occurs of oil, like in a breather system such as it becomes a solid/liquid deposit. Then that will slowly wear away, only cure is to change silicon or buy thicker stuff to begin with as it will still happen, the difference maybe visible sooner or later but it will happen, so buying thicker stuff to begin with is always a better choice. Another choice is an oil catch can that’s meant to aid and reduce oil deposits in the system
Only time I would advise other silicone is if you are working with fuel or the oil pumping/cooling side, then you need special silicone which becomes pricey as it is specifically designed to withstand long term and extreme conditions"
I am more than happy to believe him, as I’ve seen how easy it was to cut the silicon in the car where the deposits were and weren't. But for that price from AwesomeGTI, I would turn away, I have spent £160 changing all my breather piping, vacuum and TIP for that price, most expensive silicone was for the breather and I made a mount and installed an oil catch can. Heres a break down:
£90 TIP
£30 Breather piping "coupling silicone" (0.75m) + Joints
£40 Vacuum piping (3m of one size and 2m of another) with Jubilees
I bought a oil catch can for another £15 which I made a mount and colour coded the mount with the car, I will upload some pictures later of how it turned out, my only advice is if you do install an oil catch can, for it to be effective the piping must be flat level or descending when it head to the breather, ascending the piping or not keeping it level will reduce the oil catch cans effect, as the oily vapors have to travel upwards, whilst an oil catch can, catches oil via gravity, so you kind of eliminate or reduce the effect of it by having ascending piping.
It’s like fiber glassing the dots on the engine cover, then smoothing it, why not use paper-Mache, why not use that instead its fire and water proof, plus far cheaper.
Hope this helps, just my two pence
EDIT: here my engine with the breather silicon, before I added the oil catch can, TIP and replaces vacuum piping, I'll take a more recent one soon:
