The fuel lines on my s/c are rubber also (they must be fuel injection specific-should say "for fuel injection" on the hose some where).

It sounds as though your fuel line was routed, or drooped too close to a very hot surface (EGR tube).

The shops you've taken it to so far, have probably done you a favor by realizing they weren't competent to work on something that appeared "exotic/ out of the ordinary".

Metal fuel plumbing shouldn't be necessary with our s/c kit, as there is no greater fuel pressure wether s/c'd or stock...it's the same fuel pump supplying the juice.

Good Luck finding the ever elusive "competent auto tech".