Congrats on the new purchase, looks good.
The turbo on these is quite noisy anyway, so you may not necesssarily have an issue, but it might be worth getting your mechanic to check out the oil feed banjo bolt to the turbo, while he's poking around; to check for blockage. If you've freed up a blocked exhaust; you're probably getting proper boost now, hence the extra noise.
My turbo has been noisy since I bought it, and 45000km later still going strong; not any noisier, but I did pull the banjo out and drill it to 2mm.
Best of luck, and enjoy the new toy.
Cheers, Dale