I've had this same ticking/clicking noise coming from my drivers side rear axle for the past 2 months and its been resolved after a tech greased my spindle.
First dealership had the car in for 2 days and came back asking for $600 to replace the axle, they blamed my lowering springs. After some back and forth I took the car to another dealership, after that tech read the notes from the last dealership they also concluded it needed a new axle. I succumbed and they ordered the part.
Fast forward to today, i brought the car back to have the axle replaced but one of the senior techs wasn't totally convinced it was an axle issue. After giving him a ride along he had an idea and 20mins later i took the car out for another spin and no more clicking/ticking/tapping noises.
He removed the hub/wheel/axle assembly, cleaned it, greased it, retorqued and boom. Issue resolved.
If you're also encountering this issue I'd recommend you try the above solution first before replacing your axle.
EDIT: Just to be clear, this is the noise i was hearing:
http://www.ft86club.com/forums/showthread.php?t=43936