how long to install pressure plates, disk, and flywheel?
 

Does anyone know how long (how many mechanic labor hours) it would cost me to have a ACT cluch and new flywheel put into an S?

1 business day (8 - 10 hours) depending on if they run into and difficulties.

It'd probably be flat-rate anyway.

According to this shop I went to, their shop book says:

Install time: 6.5hrs.
Labor: 70/hr
estimated cost: $455.00

I have my clutch swapped by King Motorsports twice. Only took 5 hours each time at $60/hr.

$455.00 at 6.5 hours is to the penny exactally what I paid for Ganely Honda to install mine.

I think you've figured out by now that it varies from dealer to dealer. A dealer that has done it before can do it quicker than one who is about to do it for the first time.