Just for a laugh search for the same topic on Supraforums.com to see the discussion on plastic intercooler pipes. There are some dudes in the states that use PVC poly pipe (like for storm water drains) and elbows to make up their intercooler pipe. I guess if you aren't boosting up too much it would probably hold, but also check out the discussion on underbonnet temps.
It does make a kind of sense though, the original pipes were made of rubber/plastic.
It would be a great one to explain to the cops if you get pulled over!