I am about to do this conversion once my car finally gets here (3 months and still sitting in Japan)
You will need to at least paint the front guards, as you have to use the Masa conversion guards (fibreglass)
R34 GTR guards do not fit!
You will also have to change the top, if not the complete radiator support panel, so this will need painting too
along with bonnet hinges
Good luck trying to find a genuine bonnet and front bar in the colour you want in Australia
I had to get my complete front bar from Japan $1050 and the bonnet I found locally, could only find 2 and only one was under $1000 secondhand.
Expect to pay approx $4500 for parts plus fitting and painting to do the conversion
You could do this alot cheaper with a FG front bar and bonnet. but expect poor fitment and quality.
The Masa guards you will have to get from Japan at approx $1100-1150 pair
I am about to send mine to Sydney to get copied, so If you are still keen let me know.