I basically put in used gears... the guy that did my install didn't get the right torque on the pinion bearings and they got shot and I drove about a 1k miles on them, had him rebuild it, still not right, another 1k miles later (when the sound was getting bad again) my bud and I got the right torque on the pinion bearings and in the last 28k miles the sound has gotten better....
So while it may seem worth it to save the $$ I would still buy new gears... I went 20k miles not trusting my rear end due to the noise/vibration....
If you need to save $ I think the 4.10s are cheaper than 3.73s....