I can't comment on the price, but if the auction has a few days to run, the price may go up a bit more yet.
As for the bike, it looks quite good from the pics, although I always worry about custom stuff and how well it was fitted by the previous owner. I'd rather do that myself, if I was into custom.
In general, the earlier S3s are great, really great. Not quite as punchy as the 1050, but in normal riding conditions, there isn't a lot in it. I've done almost 90,000kms on mine and only ever done the services and replaced one cooling fan, because it got some ***** in it that fried the fan motor.
I've done some 1,000 km weekends with a passenger and gear, plus I commute 50km each way every day, rain hail or shine. The only draw back in the commute is my dirt bike bars are a bit wider than I'd really like for safer lane splitting, if there is such a thing.
If it speaks to you, grip it with both knees, you'll love it.
Mick