Is it worth %600.00
How was it determined to be defective? You can alway get a used one probably for about $100.00 Check your local junk yards or Ebay.
Used or ask your dealer if they can get a rebuilt module for you.
You should be able to get a rebuilt one for about half the cost of a new one and one from a salvage yard for much less than half.
The units can go bad but I usually look at them last as being the source of the trouble since they are pretty reliable. Hopefully the shop has proved the problem to be with the ECU and isn’t just guessing at it.