'99 VW Golf (110BHP) now with bigger Turbo, maybe?

My Dad has a '99 "T" VW Golf and it was the 110BHP, the mechanic he has taken it to has said the turbo seals have gone and thats why its been at a loss for power and leaking oil all over our drive.

He has just bought a new turbo from E-bay. Its the official Golf one, second-hand, but, its from a 130BHP model of the same car.

I am worried he is going to cook his engine. IS there anything else he'll need to do to his car to accommodate the new Turbo?

Cheers anyone who can help.