Or Do I have to get 19 x 8.5 35mm ?

Non brembo 5AT

 

I'm assuming the 40 mm and 45 mm number you're referring to is the second number in the tire size.
I'm sorry, but I believe the second number is a percentage of the first number. Therefore your question in incomplete. You actually need to state the width of the tier, like 240 or 245 or 230 or something like that, then the second number is a percentage of that number. So, we'll need to know the first number of the tires your considering.

'04 G35 6MT Ivory Pearl
K&N Drop In / Stillen Grounding Kit
Borla Headers/Dual Cat-Back Exhaust
Nismo Front Bumper/Side Skirts
Impul Rear Bumper/Spoiler
AirSplat.com for AirSoft Guns!

 

I thought that was offset?

 

45 ofset is usually a honda offset... you wanna be down more in the low 30's to mid 20's...

04' G35 / 6MT / Tein Basic Coilovers
Volk 19" GT-7 Gunmetal

 

Is this going on a coupe? If it is then, no you don't want those rims on a G35C. The offset is too high which will make the rim really tucked in the wheel well, think of a skate board or a train. For after market rims, you want it to be in the 20s to 30s offset. The stock 18" G35C rims are +30 offset already.

- Don't argue with idiots. They will bring you down to their level and beat you with experience.=P-

 

i have offets of 19 in the front and 29 in the rear. they are really aggressive and sit the wheels right at the edge of the car.

2003 G35 Coupe, 6sp, Laser Red, Willow
1992 Cherokee Sport Red (daily driver)

 

yes they will work. Using this websites calculator, http://toy4two.home.mindspring.com/offset.html the difference from a stock 18 is this:
Your new wheel will have the following chracteristics:
The clearance from stut housing to the inside of the wheel will be 29mm LESS
The outside edge of the wheel will EXTEND an extra 9mm,
(that is with a +40, it WILL NOT be tucked at all, but +45 will only extend 4mm, and be virtually like stock, and may not clear the strut housing)

2003 350Z & 2003 G35c
www.350zfrenzy.com
www.g35frenzy.com