NOS may become in short supply ...

[KiwiTT]

... and the price will probably go up.

Importer to pull plug on flow of nos (http://www.stuff.co.nz/stuff/0,2106,3247720a10,00.html)

[_simon_]

Have you seen the size of the canisters that they're targeting. You'd probably need a couple hundred of them to fill a NOS bottle for a vechile.
Actually I've often seen those canisters littered around car parks and wondered what they were for.