It's like you're asking me to buy you poison, I won't do it!
Seriously, it's a huge waste of money, sell your 350z + £8k you're getting a nice 370z which has already the power you're trying to achieve NA. Or short block + TT on your engine. If you ever come to sell your 350z, not many people would want to buy that engine...
Take 1-2 more weeks to think this through before you start spending