Hello I'm Mary

Hello! New member here with a question about my 2006 PT Cruiser Turbo Convertible. Loved the car since I got it in 2015, put serious cash in to keep it running but it was totally worth it. In 2023, after $1800.00 worth of maintainence, car wouldn't go faster than 40mph. I have been told it could be the computer module, or the turbo, or the transmission... but all super expensive to diagnose and likely to repair. Can anyone advise me as to the worth of the car if I wanted to sell it as is? Convertible top is fully functioning but was slit in vandalism. Body is intact with some dents and scratches. Light grey Interior shows signs of its age and has some stains but is in good shape. Newer tires, and lots of maintenance records. Always used premium gas and full synth oil. I would appreciate any input you can offer...