You may find also that you can work with him on the price. I believe his asking number to be high.
SHO reliability is sound. The aftermarket parts situation has improved -- a good thing, since many Ford parts are obsolete. If you look into this car more closely, check on 60K maintenance history. You'll want to know that the timing belt, crank position sensor, cam position sensor, water pump, double platinum plugs and plug wires have all been replaced at some point. The valves should all have been adjusted and the shims replaced as necessary to keep the clearance within factory specs. The car should also be on it's second clutch by now, otherwise, plan for one any day.
Check for slop in the tie rods and control arm / strut rod assemblies. An outer tie rod that needs to be lubrcated at the knuckle will generally let out a telltale screech -- this is often not a sign of failure, but a simple thing that a little grease will shut right up. If the temp gauge reads artificially low, you'll need a temp sender. I'd replace the sensor, too, along with the T-stat and gasket as routine maintenance, unless you can verify that they've recently been done.
If all that stuff checks, you've probably got a winner. Also, a Gen I SHO without trashed leather is a real find.