"Breather hoses" usually refers to the hoses that make up the PCV system, many of which are custom molded, and they should be replaced with OE quality parts. Fastlane probably has them for a lower price than you might think. The 2 mm ID nylon tubing is available from Merc dealers and the list price last year when I bought some was $2.20/meter. Generic 1/8" vacuum hose is okay for the 3 mm ID OE vacuum hose.

Duke