Just had a look in my workshop manual and I think you have the TCI-h ignition system with knock control, although I may be wrong. Easy way to check is to have a look at your distributer. Are there any vacuum lines going to it. If not, as I suspect, then the ignition timing is electonically controlled via knock sensors. That being the case, you can use unleaded (95 RON) too. Have a look here for a little more info:-
http://homepage.ntlworld.com/richandhazel1/Knock/Knock.htm
Ignore the above, I'm wrong and thanks for the heads up 'a9wyn'. :-[
The Haynes manual calls it an FEI system (Fully Electronic Ignition system). Although it does have an FEI control unit, I can't see any knock sensors in that system, therefore it cannot adjust ignition timing according to knock. I see there is a vaccuum line going to the FEI control unit, so that must be how it does the advance and retard.
You should still be able to use unleaded (95 RON) but it will pink and will require the ignition timing to be retarded..........stick with Optimax or Super Unleaded.
In future I'll cross refer to the Haynes manual to double check.
