My car was originally a phase II 1.2 16v, now fitted with a K4M engine.
Along with the engine swap some performance changes were made:
Simota induction kit (the same that K-Tec sells, as posted by david_129)
Supersprint 4-1 manifold
Supersprint cat replacer
Remus "cat-back" exhaust
Clio I 1.2 (E7J) gearbox (JB1-046)
OZ Superleggera rims (each one is 3.6kg/7.9lbs lighter than the stock ones!)
Im now planning on having my ECU remapped, dont know if its worth it though.
Ive done two 0-100kph (~0-62mph) tests, 7.9s measured at 100kph by the speedometer, 8.1s measured at ~105kph/65mph (to eliminate speedometer reading error), this with two people in the car.
Note that my car is quite lighter than the stock 1.6 16v (measured 1011kg/2229lbs with full tank of gas), and at the time of testing it had 1/8th of the fuel in the tank and no rear seats (I dont use them so Ive removed them permanently), bringing the figure down to ~955kg/2105lbs plus driver and passenger. The closer-ratio gearbox also helps a little bit.
Funny that Renault claims 910kg for the Clio 1.2 16v, and my has been measured close to 990kg with a full tank of gas. I wonder how much would a stock 1.6 16v weight...
PS - GRC79, what mods do you have? 140hp is a lot, my has been measured only 118hp at the dyno!