I was Ebaying today and found a site that sells really cool looking Silicone adapters, couplers and hose. The kind that all the air intakes use. I am wanting to redo the end of the Wrangler piece I have for the 4.0L American transplant to make it shorter. The question that came to my mind is; Does the heat from an Automobile engine cause the Silicone to release fumes that would damage an O2 sensor??? I realize that thousands of these things are made and are out there. But, does anyone know if these type fittings are safe? I mean let's be realistic, The big names may be using good quality pieces that don't cause problems, but how do I know these pieces are safe????? Anyone know or know how I can figure this out???? Thanks, Morgantown,Wv Mark Price