Rome's war with the Etruscans, which then started, was really a war between the republicans, who wanted to spread from their town on the Capitoline into the surrounding Etruscan kingdoms, and the monarchists who wanted to keep what they had. The Romans, emulating the Spartans, built a well-trained citizen army and over a period of time eliminated their more settled and effete neighbors. Rome's propagandists, then and now, emphasize the differences between Rome and Etruria, but they were essentially the same folk with the Roman part going through a republican political evolution and eventually surpassing their monarchist neighbors.
Roman art, city planning, and architecture also diverged, but it was solidly based on the early Etruscan model. When Etruscan style in art and architecture again became popular during the Empire, the Roman cognoscenti adored it, but they labeled it "primitive Roman" and gave no credit to the Etruscans who had really invented it. All of the "primitive" decoration in Nero's Domus Aurea is Etruscan, and it is no stretch at all to the conclusion that much Renaissance art (based as it was on actual study of the Domus Aurea by such masters as Michelangelo) is also Etruscan.
There is a further myth that not much is known about the Etruscans. It is true that their language is not yet deciphered, but for a sample of the great amount of information that is known, go to http://www.julen.net//etruscan/inet.html. For what is known about the Etruscan Language, go to http://members.xoom.com/_XMCM/Pdictus/etrmain.html.