This article is from the Chrysler-Plymouth-Dodge FAQ, by Dr. David Zatz with numerous contributions by others.
Only if your car was designed for it (see your owner's manual) or if
you've advanced the timing or your engine is knocking. According to
Chrysler and others, many high-octane gasolines have a low
driveability index, which can cause long cold start times,
warm-up sags, hesitations, and driveway die outs. Under the law,
ALL gasolines sold in the US must meet certain standards for
detergent; if you really need to "drive your engine clean" get a
bottle of Techron or Mopar engine cleaner.
Turbo engines are usually designed to use either regular or premium.
Use of premium adds power.