I have Koni's 26 Series fitted to my car, very happy with them. Those one's you posted above are twin tubes and adjustable on the car. The 26's are mono tube and have to be removed from the car to be adjusted but by all accounts are the better shock.
Have a look here, Vetruck explains the difference between both types. Also note his comment on springs to suit.:http://www.club202.com/forums/showth...99-Which-shock