[VistaBlueMarine]

Okay, first off I am in Iraq so I have some time before I "pull the trigger" (pardon the pun) on this but as a gift to myself, and to spend some of this "sand money" I've been earning, I want to replace my 18" Fanblade wheels when I get back. So since I have next to no knowledge on tires and wheels and such, I need the help of experts out here at AFM. Some info:
1. 2007 GT Vert Vista Blue (see #5)
2. I have no need or desire to buy new tires. The ones I have on her now came with her (235/50 ZR18), have less than 18K on them and have been rotated every 3K w/out any degradation at all.
3. My brakes are stock and besides possibly painting the calipers blue, I don’t plan on upgrading any part of them anytime soon.
3. I want to use 4 tires/wheels of the same size as they are now (rotating all 4 has done me well over the years).
4. Looking around all over the place online, I believe the dimensions of my Fanblades are 18x8.5
5. I have fallen in love with Raceline's GT 2-Piece Blue/Brushed Wheels.
6. Raceline custom makes these wheels but only offers full inch sizes (18x8, 18x9 etc).

So what I need to know given all that info up there:
(a) To use my same tires does it matter if I order 18x8s or 18x9s?
(b) If I can go either way with my same tires are there any advantages to 18x8 vs 18x9?
(c) What is backspace (Raceline is asking on their order form) and does anybody know the backspace on the 18" Fanblades?

I’ll keep defending freedom out here for all of you! Hoping some/many of you can “support our troops” by helping me get my ‘blue beast’ some new feet for the same shoes.

Semper Fidelis,
D.W.M.
Major, USMC
Camp Fallujah, Iraq