The cases are the R are stronger than the SP as they are sand cast. The 1198 uses vacural cast ones. They are lighter but not as strong.
The R is already 10hp up on the SP to. Slipper should be up to the job. QS is a marmite thing IMO. Some love them. I've got customers who rate the HM unit, personally I don't like them and prefer simple clutchless up changes... kinder to the boxes as well.
For racing, I'd go for the R, no question. It's what it was intended for...:)

chatting to Tony at Moto Corse today he runs an R and some other special bits like RS gearbox - tries to lift the front flat in 5th...wow!!