I live in Belgium and have exactly the same bike, though in a poor condition, i'm planning to restore it.
The bikes are Colnago Super from 1991 and were used by the Belgian Team 'Collstrop - Isoglass'.
As you have described it, it seemed to be completely original with the Suntour group.
Thanks Alex, your information is really welcome.
I guess you are referring to this bike:
When I came across it, it was equipped with a full Suntour Superbe Pro groupset. I replaced the groupset with a Campagnolo groupset to match my other Colnago's even though I highly respect the Suntour equipment. I fitted the Suntour gruppo to a good old Pinarello that is more of a daily rider.
My Colnago is in poor condition too. Perhaps the Collstrop - Isoglass team entered too many torturous races that left their bikes quite battle scared - haha.
I'd love to see a photograph of your bike. Thanks for sharing your information, it really made my day much better.