Have a search through the forum and you’ll find some really great recommendations and reviews. There are a multitude of companies offering remaps, but a few names will pop up over and over again.
IMO the DSG remap is worth it if you can do a deal to get it at a good price alongside the remap. It definitely helps get the best out of a remapped car, but it’s not 100% essential so don’t pay over the odds for it.