Dead mk4 golf pd130.. diy turbo cartridge swap?

[DegsyE39]

Evening all hope everyone is good.. My golf went into limp mode about a week ago as i was driving on the a18.. no power etc. drives like its a 1.0 litre corsa oh st, so i've plugged the car into vagcom and i am getting a p1557 overboost code, I've smoke tested the vacuum lines and no leaks there i have not checked the n75 or actuator yet as i've got a sneaky suspicion the vnt vanes are clogged full of st.. or my turbo is goosed... so sorry to ramble on but what are the ebay gt1749v cartridges like? anyone on here had much luck swapping them out? pic of my chipped turbo enclosed i just hope my motor isnt fked..

[DegsyE39]

This is the pic shuffled under the car to get.. the turbo fins look a bit fked dont they,whats the chance of engine damage here?