Hi mate I’ve got myself a mk1 1.6 16v and so far done things like , coil overs stiffer antiroll bars and an enclosed induction kit with heat shields and fed it fresh air from behind where the fog lights would be ( I had blanks there so I tied the ducting behind them and dremeled out slots into the blanking covers). The next thing I’m looking into which would work on yours too would be a sports cat (200 cell as I want to pass mots without changing it all the time !) . When I get wide band O2 installed I’d think about a remap if you go for this then get it done on a rolling road as generic maps can cause problems under different conditions with some cars . All depends on how far you want to go/ have to spend . First thing tho would be to get the best oil for it and filter and put decent fuel in it my car runs smoother cleaner on shells niro+ and at the moment I’ve tried tescos motive or motion ??99 octane , it won’t increase power but prolongs the engine life and keeps it happy