Earlier quoted context omitted.
f0660f is the top winner for World-2 right now. You will want to switch worlds! Also the cars are all slightly different if you look closely.
They're slightly different, but that's irrelevant. When you breed the two almost identical cars, you'll get almost identical offspring. Diversity is essential for crossover. And crossover is essential for genetic algorithms. Just mutation isn't enough. And right now the setup appears to be such that you'll end up destroying all diversity from the gene pool as soon as you have more than a few users.
At least with lots of players, as pubnub said, some of those identically named cars were actually different generations and different cars, but were cousins or otherwise related from a common ancester.
One recommendation would be to incorporate any mutations into the ID, so if it started f0660f and mutated it would be f0660f0b or something, to track parentage (And in fact it would be cool if crossovers were tracked in the ID too, a bit like the Russian patronym or spanish matronym)