Only differnce betweeen RSi and 16v is the 16v sits lower as std, so a 60mm kit for a 16v will lower an rsi by more than 60mm, if you get my drift, strut tops are same through out teh clio range, and bottems bar hub spacing are only different for williams, whihc runs a higher degree of castor. Rsi hubs are 54mm hole spacing like a valver's bt they will prolly request teh spacing.
As for spring poundage the valver is likley to be slightly higher(but might not be) than teh RSi, but a higher poundage spring(within reason) is onyl a good thing
General rule with suspsenion is you get what you pay for, in most cases, ie buy a cheap kit and it will be shit, buy a more expensive one and it will be better