In Donnie Brasco, Lefty said: "You're still driving a fucking Lincoln when you get there." What's that mean?

Question

In Donnie Brasco the following dialogue occurs:

Nicky: "It's a longer car. Two fucking cars, right? This is a car, this is a car, right?"
Lefty continues to watch Brasco. His friend talks from the Off: "Right here, okay? All things being equal, the one's longer gonna get there first. You don't have to be fucking Einstein to understand this."
Lefty: "You know what happens when you get there, don't you?"
Nicky: "No."
Lefty: "You're still driving a fucking Lincoln."
Lefty said : You're still driving a fucking Lincoln when you get there."

What's that mean? Does it means the Lincoln is slow?

Answer 1

You've obviously watched the Director's Cut, going by the questions you've asked. There are some differences in the script, including this section. To quote the relevant section from the original script:

Lefty: Ain't no comparison. Cadillac got more acceleration, more power, more-- better handling, better looking, more legroom for your legs , more power

... other dialogue, then later:

NICKY You got two cars. One's longer. All things being equal, the longer car is the one gonna get there first.
LEFTY Ain't the question all things being equal. One's a Cadillac and one's a Lincoln.

In other words, Lefty is arguing the Cadillac is better. Nicky is arguing the Lincoln is better. Nicky has tried to use the argument that the longer car will get there first. Lefty, in the quotes you've provided, answers derisively that "You're still driving a fucking Lincoln.". Or to put it another way, it doesn't matter if you get there first, you're still driving the inferior car.

So in summary: his comment indicates his opinion that the Cadillac is better than the Lincoln.