Ive compared c5 c6 uppers side by side... they are different t. The lowers are the same except the spring mount.. The cradle on a c6 is mounted further back to accompliah moving the wheel backward.

That doesn't make much sense that the wheels don't move when swapping the C6 cradle into a C5 and not the control arms, but they do when swapping the cradle and control arms though?

The C6 cradle is moved back in a C6 Chassis... so the location of the lower control arm mounts on the cradle, relative to the alignment pegs on the cradle, is the same for a C5 and C6, which means the LCA geometry does not have to change, and that a C6 cradle, if put in a C5, doesn't move the wheel.

The upper control arms have the ball joint hole moved backwards, given the C6 a longer wheelbase. Swap C6 UCAs into a C5 and the wheel WILL move backwards.

Gotcha. This is starting to make sense. I have read that the lower control arm on the C6 will move the wheel back 5/8" but everyone said besides that its the same. I was curious because if the lower moves toward the back of the car it will reduce the amount of caster you have. But since you explained the upper a arm has the ball joint hole in a different location than the c5 it corrects the caster loss.

So if i end up going with the c6 suspension i just need to move the rear suspension points towards the front of the car the 5/8 and it would keep the wheel centered where i want it. That makes sense. So the geometry is all though. Thats good to know. Appreciate the help guys!!