The 16i has adjustable tie bars which alters the castor, not the camber. Both early and late types of 16i have this along with the koni adjustables and the twin rollbar setup. The revisions were IIRC slightly altered mounting points at the rear? and the Sierra type top to the front struts which as you say eliminated the 'knock Kneed' look as it altered the CAMBER
The REAR anti rollbar was on the official spec but never fitted. It is the same as on an orion of a similar age but will only fit the early RS1600i's as the enlarged fuel tank on the revised model gets in the way IIRC.
16i's handle pretty well as standard so all i'd do is fit a rear roll bar if it'll fit and make sure the shocks are in good nick or replace with new. I'm not sure about fitting a full set of coilovers.......anyone else done it?
Only other thing I can think of is if it's lowered at all it may be worth seeing if you can source some camber adjustable TCA's made up to prevent excessive tyre wear and the bushes wearing prematurely...but I'm not sure if these would be cheap.