well, those bronze XD-9's would look tuff as hell. Simple.
Id get them with a 245 (or 255 if you feel so inclined)/45 R18 tyre, and MAKE THEM FIT.
Roll, flare, get them in, lower to suit. Just over the tyre is where I would want it to be. A gtr doesnt need any body mods, looks tuff as standard.
Someone said 17 x 9 +22 was a good size, those 18 x 10 +18's will only stick out 17mm forther, which can be cured by a simple roll and slight flare.
Depending on where the x9 +22's sit of course.
What do you have on there ATM, as in size/width offset? Give me that info and I can tell you exactly where those XD-9's will sit.
A photo would help too.