Hi RobbbieMeister
I haven't paid to have them done but would guess the job would take around 4 hours for the dampers plus the cost of an alignment check. In theory the installation should not affect the steering geometry but it's sensible to have this done every couple of years anyway so I would recommend you pick a workshop that can do a 4 wheel alignment check at the same time.
I am seriously considering going to Koni FSD's and have just found a local independant who could do the job. I wanted to get an idea for price before I asked him to quote.
I don't think he has the kit to do the alignment though.
I've had my FSDs fitted by the Backstreet Boys, at Stealth Racing in Southam and a mighty fine job they did too. They carried out a full alignment check and all has been tickety-boo.