Gentlemen, gentlemen,

If the benefits of the lightened flywheel are so obvious
then why doesn't Ford manufacture these cars right that
way ? 0-60 time is something people consider when shopping
for sporty sedans.

With a lighter flywheel the car has better acceleration,
no doubt about it.
What is the downside ? Worse idle, increased vibration,
overall shorter engine life. Of course this is true for
the majority of performance mods and most people around
here interested in better acceleration only, and happy to
pay its price.

T.