Hi, did the dealer say coil or HT leads, if your car has been running poorly it could be either or both! There is normally one coil to four HT leads and a module that supplies voltage to the coil. BUT, I do not know if the Clio has a module, sorry. Each of these four leads terminate onto a spark plug. Can you get a second opinion? it's a lot of money if it's only a faulty HT lead. HT = High Tension. Good luck.
Chris P.Duck, February 2010