Well here's the story, in probably boring detail :-):
SYRIZA is the electoral block that is participating in the elections, a coalition of leftist groups that has managed over the past 5 years to inspire both a significant number of young people and a lot of disillusioned veterans. Politically it is like a marriage between the Front de Gauche and NPA, with the participation of Green party members...

SYRIZA is composed of 11 component parties plus many unaffiliated leftists participating locally and nationally in the alliance. This alliance is very diverse: it includes trotskyites, maoists, post-communists, post-eurocommunists (left and right), social democrats, socialists, greens, ecosocialists, libertarian communists etc. Of these one, Synaspismos (Coalition of the Left), is dominant in terms of both electoral power (it was the only component that had parliamentary representation) and membership: it has nearly 17000 members while the next largest component party is at a tenth of that and the smallest have memberships of a few tens. This makes representation lopsided: one could argue that the rest of the component parties were nothing but an electoral coalition around Synaspismos.

After the not impressive performance of SYRIZA in the European elections, this was challenged by the rest of the Component parties. They said that the default leadeship of SYRIZA could no longer be the leaders of Synaspismos. They rallied around the popular (and generally respected)figure of Alekos Alavanos, former leader of Synaspismos who had facilitated the transition of leadership of the party to Alexis Tsipras, a thirty-something civil engineer, that headed the left's successful municipal organization in the City Council (more on point 5, here). Alavanos, in what was generally portrayed as a political filicide, stood up against Tsipras and demanded that he and not Tsipras lead the coalition during the next election (the current one). In this he was backed by all of the other components outside of Synaspismos. This was refused by Synaspismos and for a moment SYRIZA was on the brink of dissolution. The moment unfortunately was right after Karamanlis called for snap elections. Thus after a summer of self-flaggelation for not managing to increase its European vote enough, SYRIZA further lost credibility by not being able to pull itself together even during a crisis. (The European elections is possibly the toughest challenge for SYRIZA's unity, as Synaspismos is generally various shades of pro-EU, and most of the other components are Eurosceptic).

This split however was due to a more important political one: Synaspismos itself is composed of many political tendencies but it is characterized by one major split: the moderate social democrats vs. the harder left. During a time of crisis this split had many opportunities to demonstrate itself: from the events of this past December, to the turmoil in Greek universities and the focus on local movements at the expense of central political alliances and manoeuvres etc. SYRIZA being a move to the left for Synaspismos, it is no wonder that the rest of the component parties of SYRIZA, have little tolerance for Synaspismos right wing, especially because it has a much better access to media than any other part of SYRIZA and because it is seen as undermining SYRIZA, on every occasion, by publicly criticizing the coalition. It seems probable that Alavanos' moves were meant to precipitate a split inside Synaspismos...

The deadlock was broken when Tsipras announced that he would not be heading SYRIZA, that SYRIZA's representation would be collective, and the new parliamentary ream will vote for its leader after the elections.

So if SYRIZA manages to gather more than 4% of the vote, everyone will be happy enough. If it falls under 3% and loses its parliamentary representation I think SYRIZA will disolve into its constituent parts. It seems that the first scenario is more likely than the second for the time being...

The road of excess leads to the palace of wisdom - William Blake

The far-right LAOS, started from around 7% early this month, but now it seems that they will remain around 5%, though I think that people voting for LAOS might be too embarassed to tell the pollsters, so I fear for the worst.

LAOS is a cross between Fini, Berlusconi and Lepen. The scariest part is that they are being supported to a scandalous degree by the private media. Let me give you an example: in May polls political polls were showing that only 2% of voters though that immigration was a major problem, as LAOS pushed the issue to the forefront of its campaign, the media went on anti-immigrant frenzy resulting in an explosive reversal of attitudes, from 18th more important problem in less than 30 days it had shot up to no3 at 18%, behind the crisis and unemployment IIRC. Now it has fallen again to 2%. But LAOS poll numbers which had remained at around 4% for the past two years, followed the anti-immigrant trend and LAOS gathered 7,2% of the vote in the european elections, and set a law and order agenda that was adopted by the conservatives and has resulted in the deterioriation of already disgusting conditions (and public attitudes I should add) for refugees and immigrants. Right now as we speak, nazis (real Nazis with funny salutes and all) are "policing" poor areas of downtown Athens, threatening and beating "illegals" and legals alike, under the unwatchful eye of the police, which seem to view them as some sort of deputy.

I still hope against hope that LAOS might be squeezed below SYRIZA's final percentage, though that seems quite unlikely at this point.

The road of excess leads to the palace of wisdom - William Blake

France 24 | Greeks vote in snap election after crisis-hit year | France 24

Opinion polls show the socialist opposition in the lead as Greeks vote Sunday in a snap election called by PM Costas Karamanlis (photo) following a tough year for a country battered by the economic crisis, riots and corruption scandals.

AFP - Greeks began voting Sunday in a snap election in which the opposition socialists were tipped to ride into power on a wave of anxiety over the country's looming economic crisis.
  
Led by former foreign minister George Papandreou, son of late prime minister Andreas Papandreou, the socialist PASOK party held a lead of 5-7 points over the ruling conservatives in the final opinion polls published two weeks ago.
  
Prime Minister Costas Karamanlis called the snap election halfway through his four-year term with his New Democracy party, stung and distracted by corruption scandals, finding it increasing difficult to govern as the country faces a dire economic crisis.

Thanks and congratulations!

"Dieu se rit des hommes qui se plaignent des conséquences alors qu'ils en chérissent les causes" Jacques-Bénigne Bossuet