In the MK7 and 7,5 the GT type models always had the option of the Ergo Active seats which not only had extended seat squab, but also massage function. For some strange reason VW decided that the top tier models didn't need the extended squab version.
My guess is that on the MK8, VW will follow suit and offer an Ergo Active seat to some of the lesser models and nothing for the performance models (at least not in the images I've seen of the GTI and R interiors) ?