The S uses the same belt as your Super 8.
I picked up a super special elf-made Malossi uber kevlar belt for the S from Scooterworks last year, no issues last I heard, but I did sell the scoot a couple thousand miles after I installed it.
Scooterworks has the worst price on belts so I'd shop around a bit vs. buying from them. I had ordered a bunch of other stuff from them, so shipping was already covered & I was pressed for time, or I would have as well.
You may also want to check the forums and see if any other brands, Dayco, & Gates for example, are any good. I believe they run a bit cheaper, but there were some questions about life and durability when I checked.
Do be a bit leery of Ebay of course. unless the seller has a significant history.
There were a few reports a while back of folks getting either the wrong belt & the runaround on exchange/refund, or a belt that was very obviously the cheap knock-off (made of used chewing gum) vs. what the auction stated.