Headliner. Typical '80's headliner: sagging and annoying.
Master cylinder: car stopped very well, but would not hold the car stationary at a stoplight (lost pressure. Had to put it in neutral and use the emergency brake. However, it was an inexpensive repair at my local mechanic's).
Transmission pan leak.
So far my shadow has been very reliable, a blast to drive, really comfortable, and economical. It's never left me stranded.
UPDATE: three years later and I still have this '88 Shadow. Apart from normal engine and trans servicing (tune-ups, fluids, a couple of hoses, etc), my little Shadow performs beautifully. No major problems at all.
Looks nice, drives nice. I'll be keeping it for a while yet!