Leaky calipers...replace or re-seal?

[AuburnRyan]

My rear calipers (or at least 1 of them) is leaking....so Nissan of course wants $600 for the rear brake job...but NO, I'm not that dumb...my rears have always produced more dust and gunk than the fronts since I bought the car last june. I wanna get it fixed now that the weather is again permitting

So my question is...Do I go to autozone and buy the new (rebuilt)calipers for $75 each, or do I buy the "re-seal" kit from Courtesy nissan for $35 for the entire rear end? Is this a DIY "re-build" or am I better off with new parts? How difficult is the rebuild/seal? I can't imagine what it entails but wouldn;'t think it difficult?

Thanks