<<Are these things rebuildable, or would it be better to buy a good used
one?>>

Pick up the blower and get the "Zone" on the phone.

If I remember correctly they have the racks for about $100.00 and some
change (exchange price)

Yes they are rebuidable, and yes the Zone has a lifetime nationwide no
questions asked warrantee.

I'd give them a shot first and save your bicepts from the manual
steering treatment.