The S series is discontinued. If you check the (U.S.) website you’ll see they are now marked SOLD OUT.
My dealer has a S/510 six-pack line array on demo, and they are blowing those subs out at 1/2 price. One customer bought a pair. I found out the other day and bought the other two pairs, to add to the pair I already have, so I will be dialing in my own six-pack soon.
My dealer says the new series is coming at the end of the year, but told me they have no idea what the changes are going to be.