Used blower- what to look for

Check to make sure it spins freely and does not make any noise. Not sure of a way to check the internal belt unless you take it apart.
How many miles?
What pulley? Would be best if it has a 6 lb pulley, over 3", that will mean it has not been overspun. You can change out the pulley to a 9 lb pulley. If it has the 6 lb pulley, it probly will not come with a recirc valve due to the low boost. Even with the 9 lb pulley, you will probly not make 9 pounds of boost. I only got 6 psi on the dyno with my 9 lb pulley on my Cobra.
I got mine cheap used also, had it for over 2 years with no issues. I might just be lucky.
You should get it, it is a cheap way to get into a supercharger as I'm on a budget also. I gained 90 rwhp with the addition of the Powerdyne supercharger.

check my recent new threads... i just asked this and there was a great link to powderdyne users REVIEWS .... and where are you located... i ran into the same deal but did not follow up the impellar fins were a bit messed up and he didn't have the FMU

muncie indiana

What about mountign brackets, and all of that stuff.. I have seen a few GREAT deals that have cost almsot a new blower KIT due to missing a couple small items...

Is it still on the car???