ive done this before when i took my stock turbos off my r32 gtr and replaced them with -7's on my old GTR, with the right tools wasnt tooo bad
started lunchtime on sat and finished by sunday avo, i had all new gaskets, and everything ready to go so i didnt waste time
hardest was getting the banjo bolts off and back on for the oil and water lines to the turbos, i used crow feet spanners with an extension.....