I don't think it would be the cause of petrol fumes in the car, the OE DV failing or a vac hose coming loose just caused the "turkey" noise and no noticeable loss of power.
Which CDTI kit did you fit? Does it route the pipe from the top of the cam cover back into the air box, or have you got it just going to atmosphere?
EDIT: Also, does it sound like this?
https://www.youtube.com/watch?v=mqzRtkyhwTM
That is the noise of the OE DV working, you can just hear it more because of the holes I drilled in the air box. Apparently fitting the CDTI kit makes the turbo noise more noticeable because you loose the noise cancelling affect of the cross over pipe.
