Is the roof electric or hydraulic? - The electric ones are notorious for shredding gears and being a sod to set up...microswitches everywhere. Also, have you tried lowering the hood or are you taking the sellers word for it?, as the electric ones don't operate manually.
It's a 9-3 so the roof is hydraulic and they are about as tempremental as the electric ones in the 900ng were just without the gears to shred.
@Robson3022 If you need any bits let me know as I broke a '99 9-3 recently and still have a fair few bits kicking around. I'm pretty sure I've got a standard airbox in the shed you can have for the price of postage.