Walk away pal. When you see stuff like that and in the add the seller is already telling you " needs this, needs that" that should throw up huge red flags.
I know I am repeating myself but it is worth saying again. On items like blowers, heads, engines- anything with moving parts- unless you know the seller or can physically inspect the item be very careful. Too often you are buying either broken, well worn (abused), incomplete, or worse stolen items.
On any used blower before you even consider buying it, get the serial number and see if it has ever been serviced. Get pictures of the housing, impelller and all the pieces the seller says comes with it. Ask for his receipt of purchase. Assume that it will need a service unless the serial reflects it was recently done- and then ask yourself why is he selling it? Did he lunch the head units? Is he changing setups? If I had a dollar for every low mile, no shaft wobble, I just tested the unit used supercharger for sale I'd be a millionare. lol
There are deals out there, but there are more nightmares if you ask me.