Used SHOs

The engine is extremely durable and doesn't require outlandish maintenance, but is susceptible to rough running due to dirty throttle bodies and sensor problems. However, high mileage engines treated with infrequent oil changes are known to spin rod bearings. SHOs are very hard on clutches; you'll want to ensure that a car built previous to February 1991 has had the factory clutch upgrade performed. Signs of clutch wear (thanks to Dennis Krebs):

Sometimes, shady shifting problems can be solved with nothing but synthetic transmission fluid, so if you're dream SHO won't shift into reverse easily, don't give up on it.

Many SHO owners will dump off their SHO right before 60,000 or 120,000 miles to avoid the expense and trouble of the 60k tune-up.  It is always a good idea to ask if the 60k/120k/180k tune-up has been performed and if it hasn't, adjust the price accordingly. 

Taking a look at the intake can reveal motor mount problems and bad subframe bushings.  Shiny spots visible on the intake manifold that appear to have been rubbed in a vertical pattern usually indicate bad motor mounts and a horizontal pattern may hint at bad subframe bushings.   

Oil in the plug wells - a VERY common SHO problem.  The cause is bad plug well seals.  Signs will be rough running, and oil smoke out of the tail pipes.  This problem is usually indicative of a SHO in need of a 60,000 mile tuneup.

Radiator and other coolant leaks - I don't know if I've ever seen an SHO without one!

Broken climate control buttons - Again, I don't know if I've ever seen an SHO without one!  I would invest a little more in an SHO with good climate control buttons - you know it's been babied. 

Also, the battery is in a poorly ventilated location and suffers a high rate of heat failures, so you'll want to pay particular attention to its age and condition. Particular problems of Tauri in general include warped front brake rotors, steering graunches, splotchy paint, water leaks around the trunk, and rust. The mechanical problems have been addressed by Ford technical service bulletins for the most part; you'll want to look for proof that these have been performed on the car you're interested in, or else deduct the service cost from your offer. It's a good idea to call the NHTSA Technical Library and get service bulletin info for the model year you're after (see Appendix A ). For general car-shopping advice, my personal favorite is Remar Sutton's excellent Don't Get Taken Every Time (Penguin Books, $9.95).