I think the idea of Tarquin as some mustache-twirling tyrant is a bit iffy, given that literally the only source we have for any of this is the accounts of the guys who overthrew him. Case in point: Domitian was portrayed as the second coming of Caligula, but upon more objective research we can see he was an able if autocratic ruler. I think it's more likely that Tarquin was rebelled against because he was Etruscan, and we definitely shouldn't take the story that he was a kinslaying, tyrannical rapist at face value.