I made one fit mine Mark, but no they don't fit directly. I ended up fitting a rubbber sleeve over the thread and using a grub screw to secure like the aftermarket kits like Momo do
I know that the Spec R 6 speed is a M12x1.25 thread, but I don't know whether a Spec S 5 speed one is the same M10x1.25 as S13/14's.
Might be worth looking into.