I'm about to purchase some new shoes for my 07 V6.

The dimensions are 18x8 35mm offset/5.90 backspacking, and 18x8 45mm offset/6.29 backspacing

Will these look right on the car?

 

Why would you use the same size wheels with different offsets, presumably front and back pairs? Stick with the 18x8 45mm offset wheels all-around, and you should be ok. The dimensions of the stock 18" S197 wheels are 18x8.5 with 50mm offset. You also didn't mention what tire sizes you want to go with, that makes a difference in both fitment and looks.

 

I believe it's because the rears are concave in design.

I'll be running 255/45/18 all around.

 

I personally wouldn't run different sized wheels front in back unless I had very good reasons to run a staggered setup, and even then, I'd be going with wider wheels and tires in back.

The tires shouldn't be a problem with fitting the car or wheels, but running different offset wheels front and back will definitely affect your ability to rotate your tires, which could lead to shorter tire life. I'd recommend sticking to the same wheels on all 4 corners.

 

If the wheels have a concave design to them the less offset and backspacing would be better. The 45mm would be sunken in the wheel wells while the 35mm will be push out a bit giving you a wider stance and more flush look but not completely.

Do you have pictures of the wheel or a name?

 

Bremmer Kraft BR05's

 

Those are nice looking wheels. By the looks of it the 18x8's don't have much of a concave look to them vs 18x9's where it's most noticeable.
I checked and they don't make the 18x9's in our car's bolt pattern.

 

So what size should I get all around?

 

I think the 18x8 35mm offset wheels would probably look a little better since the tires and wheels would be pushed out about 1/2" further than the 45mm version. There won't be a lot of difference between the two different offsets though, just get the same wheel on all four corners.