I am building a Sky Star Series 5 Vixen. I have read enough on Team Kitfox about problems with trying to coat early fuel tanks that I won't go that route. I can buy new alcohol-proof ones for (only!) about $1200 and wait 8 months for them, or I can use the ones I have and never use fuel containing alcohol. I have first-hand experience with TCP (tri-cresyl phosphate, found in Decalin Run-up) and it does do an excellent job of keeping lead deposits out of the cylinders of a VW-based aero engine in a friend's Cygnet, and it appears to be compatible with the early fiberglass tanks. What I have never seen on Team Kitfox is whether anyone has made aluminum tanks for the Series 5-7. Seems doable within the $1200 price range, or am I being naive? It would certainly solve any fuel compatibility problems.