Just posting this to help out people who come across this issue

The 2008-2010 models use a different method of bolting on the rear cv axles (for RWD models at least, not sure about AWD)
most companies that sell the new cv axles (autozone, rockauto, etc) only sell the cv axles for the 2011-newer models and they bolt directly into the differential so theres no threads on the cv axle it just slides through the holes and bolts into the diff.
what i did was just get a cv axle from a part-out g37 that was made 2008-2010 and those have the threads directly on the cv axle.