cv joints are easier than it seems. It seemed difficult, but afterwards you'll think it wasn't such a big deal. Like the previous poster said, you basically undo the big nut and pull out the axle. There's some minor steps in between, but that's basically it.
For the rear suspension, my guess is that you need some OEM springs. They are also easy to replace as long as you can get them compressed (and since they are the backs, it can actually be done with a floor jack, and with the strut installed on the car if you're lucky).
From my experience, there are two "sometimes" difficult parts in swapping out axles:
1 ) Sometimes the nut needs a 10 ft breaker bar to come off
2) Sometimes the lower ball joint will refuse to pop-apart
Other than that, it's an easy process in general.
On the never-ending quest for better gas mileage...