I owned my valver for 2 years and it was absolutely spot on. Never had any serious problem with it, and i found it to be EXTREMELY reliable, even in winter. Has always started first time, every time.
Unfortunately though, after 121k of pretty hard miles, the circlip went in the gearbox, and therefore was fooked.
Needless to say i dropped a williams engine + box in there this weekend just passed with my mate AmirClio and she's fine again!
Buy one, but make sure you buy it off an enthusiast on ClioSport with loads of history and loads spent on it, and you'll be laughing!
My valver engine still runs absolutely perfect on 121k, smooth from idle, even smoother when warm, no tappets, no dodgy chugging, nothing. Find the right engine and you will be fine.