I am looking to try and replace the regulator on my daughter-in laws a4 b6 cabriolet, have looked on line at various instruction videos most of which are the a4s with the window/glass frame on the saloons etc, can not find much about the cabriolet. My question is, does the whole unit, with the side window rails have to come out of the car as with the saloons, or do you have to do the fitting with everything in place on the door. Any help would be much appreciated before I start the job, thanks in advance.

As far as I know the glass comes out the top without the frame as it's frameless.

That being said you still have to remove the door card and several plugs etc. Easy enough to do

Thanks, that's what I thought, someone told me it had to be done in situ which I thought would be a very if not impossible job to do.

It's not impossible, just nuts and bolts! You just need the right tools and in typical German car style, there are lots of torx bolts of all sizes!