just bear in mind that once you are flagged TD1 by any dealer, its saved in central Audi systems and there is no going back!
APR reckon they have a footprint that doesn't cause a TD1, but I dont buy into that, any change on an ECU can be flagged if you know what you are looking for, as would any increased boost etc etc.
anyway, i'd LOVE to do it, but the cost of replacements with no warranty is enough to put me off.