I love old Opels, including the Monza (and the Commodore), as well as the Manta. Though the Manta, at least in germany, has quite a few stereotypes attached to it (fox tail, peeing in your boots, mullet, dumb blonde on the passenger seat etc). Most “old” stuff from Opel is lovely, made like they meant it.
To me, that probably stopped somewhere around/after the Calibra (which i do like too).
If i had too much disposable income, i’d go hunting for a Kadett B Coupe.