If you choose NP, I wouldn't go for the RS:Slalom.
In my opinion, the RS Racing is much easier to control in the high end and much more stable. It's just a much easier sail FOR EVERYONE, not only for the pro's.
I know that some speed addicts like the RS:Slalom, but I find it very nervous and "too direct" compared to the RSR. I was always very quickly overpowered with the RS:Slalom.
Just my personal experience.
IS87 / IS101 / IS122 / US147