Three topics/people/projects come to mind:
1) An Eastern European chap on here has built a Super Touring spec Clio (used a Laguna BTCC t-car as a donor) which has a mental amount of GFRP/CFRP aero bolted to it. Bear in mind this is full race spec and therefore comes with the price tag of one-off composites...
2) A French chap on here with a white 182 painted, as tacky as it sounds, the central/lower part of his rear bumper matt black. IMO it looked great, though I think that's mostly down to the black/white contrast.
3) There was also a member who literally bought a 197/200 diffuser and, lots of money, cutting and gluing later it was attached to his Mk2 172 bumper. IIRC he took it off fairly quick as the mk3 rear is just too different a shape to the mk2 meaning the diffuser was too wide and chunky to "fit in." Also required a home-made modification to move the exhaust tips outwards by a foot or so.
As per above though, is this for looks or are you trying to make a home made aero pack for a 1.2 clio?!?!?!