In January, I ordered an FC660C from MK.COM, and it arrived in March, I think.
It was the unsilenced version. Had I known that a silenced version was on the way, I would have waited for it.
The tactility of the 45 gr. 660C was a little more than I desired. I am now told that Leopold's '45 gr' is more like 50. It was also a little louder than expected.
The silenced version would be more desirable. It might lose some tactility, but with Leopold's weighting, that might actually be a good thing.
Ultimately, I sold the 660C. I just didn't need a board that compact. Plus, I prefer the VA68's layout over the FC660.
Now, I have to find a way to get a Realforce R2 PFU edition. True 45 gr silenced is the way to go. But it's 400 USD to import to Canada.