Some blogs I've read state that whilst holding it on the brake the clutch is at constant biting point? Is this right and won't that shorten clutch life considerably?
The DSG box has two wet plate clutches and these are designed to last the lifetime of the car. Once you remap there will be extra wear and maybe even some clutch slip
at times, but overall the capability, lifespan and performance of the clutches will be much better than an equivalently modified manual.
If you are looking at an '06 model then you will need the DSG service in one year, which costs between £200-300 depending on where you have it done. At the same time the cambelt will need changing (manual or DSG), which again will cost.