The terminal velocity of a penny is at least 40 km/h. A Porsche would be much higher. Assuming the Porsche fell that slowly and reached terminal velocity instantly, the cliff would have to be 20 km high for the Porsche to fall for 30 minutes. Given Mt. Everest is just under 9 km high, you would need more than 2 Mt. Everests of height for your cliff to make this happen.
Based on all that, the terminal velocity of a Porsche is irrelevant.
The terminal velocity of a penny is at least 40 km/h. A Porsche would be much higher. Assuming the Porsche fell that slowly and reached terminal velocity instantly, the cliff would have to be 20 km high for the Porsche to fall for 30 minutes. Given Mt. Everest is just under 9 km high, you would need more than 2 Mt. Everests of height for your cliff to make this happen.
Based on all that, the terminal velocity of a Porsche is irrelevant.