I have a FK '05 and always hated the original shocks, already since they were on my Corally C4.1.
I have now mounted the Serpent 960 (rear) shocks , and they are just fine !
very easy to build, same lenght as the originals.
they are totally closed on top, you mus open and fill them at the shaft-opening, underneath.
they are made in Holland.
Serpent part nr: 903165, shockabsorber-set RCC-1 RR (2)
so 2 pieces per set, and be sure to order only the rear (RR) ones !!
how to build them:
serpent 960 shocks