The engine breather hoses on the 30v engine are made out of a lovely thin walled plastic that apparently can not take heat all that well. As long as you never touch it, it seems to be fine. As soon as you touch it, it breaks very very easily. I have struggled with this for a few years, never really finding a solution to it till now. (the big reason for this struggle is, the pieces are very expensive, the large one that goes from bank 1 over to bank 2 is over $90..)
During recent work, I broke the breather in 3 places on my A6.. I looked around the garage, till I found some blue plastic conduit, for home wiring. I figured, hey, worth a shot. It's about the right size.. So, a little heat, a little streching over a 3/8 ratchet extension (the fat end), a little bending, let it cool, heat a little at the ends to fit the hose, a little rubber cement, and presto, perfect fix.
The only unknown at this point is how well it will take the heat. I will update this as soon as I have some findings.