check out demon tweeks and cam racing, as well as google for twingo 1.6 coilovers and you'll soon see what coilovers are available for your car. i think you're in the wrong car to be slamming it as i don't think anything exists, and rightfully so. pretty sure 99.9% of the members on here who own renaultsports will tell you the same thing. the lower you go, the more you take away from the renaultsport charachteristics thus messing up the bump steer geometry etc etc...that's fine for a piece of crap that has no renaultsport wizardry like a clio 1.2 - slam away!
however i have seen one or two decked twingo sports on this forum so have a search through the search bar. i'd link you if i could remember who lol
i have lowered mine quite some with shorter springs in the rear cause the origanlly from ST suspension werent enough for me but i still run quite high for the "lowered scene" , but if you run stretched tires you can practicly run 4 cm's off the ground , but is it healthy for your driveshaft i dont know
i think the lowest in a 133 would be OllieCup and then me