Building up rear - best axles and differential?
 

For axles, I was looking into Strange's and for differentials I've been recommended Auburn Pro limited slip. I already have 4.10's. I just realized though, will I have to reinstall the 4.10's? Wouldn't mind doing that anyways since I have a howling in the rear end when decelerating.

I am running an Auburn Pro diff with 31 spline Moser axles.
No complaints about them. The Auburn Pro diff is TIGHT! It does differentiate during regular street driving, but it is much tighter than the factory unit it replaced at ~30,000 miles.

Pretty much any brand aftermarket axle is going to be good(strange, moser, or any other reputable brand. Don't know much about diffs, but you don't have to change the gearset unless you want to get rid of the howling which requires setting up the new set properly. Once you run an improperly setup gear the whining is permanent and can't be fixed.

I'm looking into Strange's since they're a bit less money. Only thing is that I think I'll need new studs with these, which I don't mind.