Are the front and back equally important? Def want to do the rear but not so sure about the front. I would have guessed that the front would be MORE important than the rear but who knows, im not an expert. Seems kind of weird to only upgrade the rears but not the front, doesnt that create uneven handling with new rears but stock fronts?

No - just do the back. The stock G35x front sway is oversized (to induce understeer stock, likely - one can postulate, based upon the target demographic of the x vs the rwd models.) Increasing the front sway at the same time (and there is no stock option; the x's have the largest front sways in the lineup,) will just induce understeer again.

Only upsizing the rear (to the stock journey sway,) is effectively the same as increasing the journey front slightly.

Effectively, you're bringing the ratio back around to neutral, (as opposed to a slight oversteer bias, which the journey has)