The RSi is a good warm hatch if you consider it in isolation. It has decent urge from its 110bhp 1.8 8v engine and has sports trim, side skirts and alloys. It develops a similar amount of torque as the 16v, but at much lower revs - that doesnt make it as fast, but it does make it more relaxing to drive.
But youre not considering it in isolation! The 16v was designed as a proper hot hatch from day one and there are major differences between it and the RSi. In effect, the RSi is a stanard car with some nice trim and a good engine, whereas the 16v is a substantially altered car.
The 16v has wider tracks, a different rear suspension system, beefed up bodywork (including the legendary bonnet bulge and arches), higher spec brakes, -40mm lower ride height, uprated shocks, different interior, revised transmission system...not to mention a belter of a 16v engine!
The 16v (Williams) F7P (R) Clios were rallied in Group A during the early-to-mid 1990s and still hold many tarmac stage FWD records. The 16v and later the Williams were the homologated cars:
http://images.cardomain.com/installs/286000-286999/286766_3_full.jpg