I was brought up in a car family, my dad loved cars and I was taught the art of making an Austin 7 operate.
I have about 40 cars, of which 25 to 30 are what you might call serious.
It indicates the speaker's extensive car collection, consisting of approximately 40 vehicles, with a significant portion considered valuable or noteworthy in terms of their importance or performance.
The GTO is such an important car because it's a racing car and a touring car and that's pretty unusual.