Silicone hose should not be used with oil. Black will not show as seepage as easy as color hose. I know I will not install silicone with oil parts. I have Installed MANY MANY MANY of the metal tubes over the years since these cars were new with lots of different turbo sizes and zero have leaked or seeped. The spacer is not a leak issue. If you do not like the spacer there are other ways such as we include with are large turbo kits.