overheated today, beware

had it overheat yesterday due to a bad thermostat. was only about 9 months old and came with the metal housing from o'reilly's I think. I cant remember. it only took about 20 seconds to go from normal to pinned in the red. probably was 260-280degF. wish the temp gauge actually showed numbers instead of just hot and cold.
the car's fine but probably wouldntve been had I not noticed just when I did. thank God I smelled the coolant and immediately looked at the gauge. wish these cars would chime when something is VERY wrong to get you to check your gauges like the newer vehicles do.
id like to add that I really didn't notice a difference in performance even when it was all the way up in the hot. I noticed because I was smelling dexcool. it couldntve been more than 20 seconds because I am always checking the dash. probably was a cheap t-stat. I wonder if this cars ecm is smart enough to start richening it up and retarding spark as it overheats to try to mitigate it? anyone know?