S4Rs takes a 46mm socket for removal. It is best to use a wheel removal socket specifically made for this job so the socket doesn't jump off the nut. I bought mine through Corsair-Industries.com. Get the six sided one. It's money well spent They make a lot of great tools for Ducatis. Beware of cheap ones on the market. Good luck. That nut is torqued down sometimes over 140 ft/lbs.
S4Rs vs 1098: indeed the seating on the S4Rs is more aggressive than the old M900/xxx but it is still a far cry from the 1098. Perhaps it is my height (5' 7") but on the 1098 I was forced to turn my neck way up to see forward. I guess someone with longer arms may not have this problem. In my case this pushed a lot of weight on my wrists and a lot of strain on the neck muscles to hold the head up, especially under heavy breaking. The deciding factors was the two seating arrangement. My wife loves Ducatis (I know, how cool is that!) and she supported me when I wanted to try the 1098 but it was basically unusable for weekend rides for two. The S4Rs is a much better all purpose bike sport bike, love it and I use it nearly every day. I still plan to add a 1098 or 848 to the family one day just for the heck of it but it will have to be an addition, not a replacement. The good part of riding a 1098? The ride on twistiest is unbelievable. You can almost hear the bike saying "I know how to carve turns like a champ, just sit there and do not touch anything!"
UPDATE: just completed the replacement. Please do note that the 4 pins on the hub MUST be aligned with their socket visually when you replace the wheel. If you do it wrong, the wheel will still sit "ok" but obviously you are going to damage the wheel and possibly the hub if not hurt yourself. Do not trust the fact that the wheel appear to be locked on without play, that does not guarantee it is on right!