This is stuff you need to do, and you need to do it regularly. If your car is stalling or running rough, START HERE! This isn't just a good idea for the SHO, but for your other vehicles as well.
Oil ChangesFrom 1990 to 1996 I lived in Detroit Michigan as an Automotive Electronics Engineer. I was involved in all sorts of projects (including some stuff I still can't talk about), and heard lots of different car stuff that would blow your mind.
Here is a story I heard from my friends at General Motors:: GM took 20 Corvettes and filled them with Mobile 1 oil. They then ran the cars on their test track, continuously, for 200,000 miles. Half of the cars had their oil changed every 3K miles, and the other half every 10K miles. At the end of 200K miles, all 20 engines were disassembled and examined. In the words of GM, "there was no significant difference in wear" between the engines that had their Mobil 1 oil changed every 3K miles and those that had their Mobile 1 engine oil changed every 10K miles.
When I was in college, I had a 1979 Monte Carlo which I got new. Starting at 20K miles I changed the oil with Mobile 1 every 8K miles. When I sold the car, with 180K miles on it, the engine still purred.
Recommendation: Change your engine oil every 10K miles. Any sooner and you're pissing money away. Use either Mobile 1 or Redline oil.
Transaxle FluidRegardless of what the book says, change the tranny fluid in your manual or automatic SHO every 20K miles. This is what's called preventative maintenance - you do it to prevent expensive transmission maintenance later in life.
Oxygen SensorsThe O2 sensors send vital information back to the EEC-IV module. Timing, horsepower, emissions, and gas mileage are all dependant upon the O2 sensors. O2 sensors do not age gracefully - they fall apart like an old pair of shoes. As they degrade the EEC-IV module will attempt to compensate for the inaccuracy of the readings but after awhile the compensations is more guesswork than anything else.
Replace the oxygen sensors every 80K miles. It will improve drivability, help you pass your emissions tests, and improve gas mileage.
Spark Plug WiresThese degrade significantly over time. Replacing the spark plug wires on your SHO every 80K miles is like a facelift for your engine performance.