Reliability is a Rational decision.
A Luxury car is an Emotional decision, a Used Luxury car is a hopeful decision and a Convertable, Used, European, Luxury car boarders on the delusional.
And as Mustangman pointed out, maintenance will be costly and I’d add that the initial cost, repairs and and insurance will bleed you dry.
“If you can’t afford a new one, you can’t afford a used one.”