Very unlikely. Unlike Syria or Venezuela, the Iranian regime has an ideological base and a very solid base of supporters. A civil war has more odds than that base of supporters accepting a new secular regime.
Popular revolutions will sweep any ideological base away, and it appears to be underway. The scale of the protests in the clips that have made it out have been impressive.
I can't see that it would be anything other than guesswork. Polls are unlikely to be possible with any accuracy there. This is anecdotal, but I've heard from the few Iranians I've known that much of the population lead western lives behind closed doors. Their civil subjugation seems to come from the threat of violent punishment (torture / rape / death / disappearance) and a Stasi-esque domestic intelligence network.
Small sample, but talking about this with my Iranian friends, the sentiment among them and their wider network is that they do acknowledge that Iran has problems, that they need a change in leadership, but that they do NOT want a regime change at the hands of the US/Israel. For them that is a recipe for disaster and more carnage.
In their view, the topology of Iranians and their political views would be: 10% - pro-US regime change intervention; 20% - ardent regime supporters; 70% - pro-regime change but without US involvement.
