If i want to run 35x12.50 15 and 15x8 4.0 backspace crager 8's what do I need ? Just wheel spacers ?

 

I'd say as long as the 15" wheel fits over around your brakes (caliper, etc.) you should be fine. You'll probably need to remove your air dam underneath but you'll figure that out pretty quick if you rub at full lock.

 

I'd put on at least 1.5" body lift as well.
You'll prolly rub your fenders when turning hard over and articulating (as in off road crawling over objects and or very uneaven surfaces).

Which is the point.

And consider this. the highest they can comp your computer is to 32" tires.
I have 35"
When my speedo is at 70 mph I am actually going 75 mph.

So thats the error between 35" and 32 inch.
So a 33" tire the error would be tiny.
The difference in road clearance is only 1"

But the difference in power and milage would be IMHO significant.

When My tires are shot I will be going DOWN to 33" or maybe 32" even.
They will handle most everything want to do and a lot of mistakes as well.

Now if you have a 4 door then I would go with 35" as the longer wheel base loses you some clearance.

Just some thoughts.

Good luck and enjoy.!