You don't say what year the car is but for my money I would recommend that the turbo variable vanes are cleaned using a specialist cleaning solution.
Once this is done then it needs a proper hard run, not short-shifting on the gears but holding the revs up before shifting which will give the engine chance to clear its lungs.
Basically the carbon build up in the engine (EGR was testament to this occurring) and the turbo sounds clogged up also.
Listed below are links to cleaning products on ebay
https://www.ebay.co.uk/itm/331754313002?itmmeta=01J3JT0ARSVRG19F0E89P969TC&hash=item4d3e19152a:g:h5EAAOSw4Ehag~qM&itmprp=enc%3AAQAJAAAA0LTnITF3WGt3YJY4GI1hUKC%2BXP8ZHDRtSSnJ0dz0Rze3oyI4yeaUUtHVxMrZSc8hqxwfqLisgsWyg85fXSsypUG5TEPjryqdAfyY7W0poyavbKcZLCIPwk1KgAFZO6qaGbOFjvn1RJum1QmKPRgTz5T3wr1RkbfI2niLRxM5%2FHUmI3a19zKlItfpQ8dEqr7WSsZtiOO12fmwelgmXZ%2BWxQSEopwQ2bGvgZJsvk%2BEomby%2BYQQ9uGCpQNFJh2sOFE%2FRgKXXEAEicjKF7Fru2L8AsE%3D|tkp%3ABk9SR8CsgdqcZA
https://www.ebay.co.uk/itm/323958600044?itmmeta=01J3JT0ARVD0SDHSEBS2XS4RF5&hash=item4b6d6ff16c:g:basAAMXQfvlSg4~P&itmprp=enc%3AAQAJAAAA8MH81HR74rsuLLW6RBEnYbAOqZYRUJYaoT%2Bm13iI9d2GPBy%2BYMVauztqaiv2BhPDSQiUmH0mc8p9%2BlYvVgxiOqgQxqzxbULCTfwUvJO2BKw62hwA9eHFvDJaQPDJNL41sKqqH%2BtHdNHn994uhyIpMHCRj%2FsMAhrUEAFcWY%2FGnPf7AajOJv26HNE8JABGeaYZ1IyMJbV2HR%2B0aKL31GMCxHH3f64fVwTk8nlZRGNPeYmAFgEZrm4ne3oEDEiXKmrFLXhk3NLlGLDqex6gCZzr0e5xoFWhPsjRLqfMB2FvJfhJJbMRIwliczhp4cFCUmWn3A%3D%3D|tkp%3ABk9SR8KsgdqcZA