In regards to Saudi Arabia, the conflict extends past the shiites vs. sunnis religion. It also includes the natural resources of oil and gold. The most recent tensions erupted over Saudi oil exploration in an area that Iran claims as a prohibited border, while Saudi Arabia accuses Iran of getting a little too close to their own Gulf territories. Saudi Arabia is the number one source for exported oil, and Iran keeps searching for a way around the sanctions for their own exported oil. They discovered a deal with Turkey of trading oil for Gold, it was an "in your face" to the U.S. sanctions that are in place to protect from international trade with terrorists. Turkey says, "We didn't pay them in dollars, we paid them in gold." The animosity between Iran and Saudi Arabia continues to grow, as they both support different forces of the Syrian conflict. Iran backs the Syrian government, while Saudi Arabia backs the Syrian rebels.
Syrian President Bashar al-Assad is like a runaway train. He derailed before the uprising began, yet he's still running. If it weren't for Iran, his lead supplier in arms, he would have ran out of steam a long time ago and possibly relinquished power. He swears he would never use chemical weapons against his own people. Many governments are observing, waiting for him to cross that red line so that they may respond.
"Get on out!" is the message from the Iranian shiites and Syrian alawites to the sunnis in the Middle-East. The shiites and alawites hold similar Islamic views, and accuse the sunnis of religious persecution. The "Get on out!" message comes with more force in an area such as Iran, where shiites are the majority. In Syria the alawite government is a minority, while the Free Syrian Army is mostly sunni and the majority, that message is not taken lightly.
Iranian President Mahmoud Ahmadinejad must consider his moves. Does he obtain the most benefit from the misfortune of the Syrian Rebels, or by siding with the regional powers of Egypt, accepting the benefit derived from the misfortune of Syrians President al-Assad. If he sides with Egypt, he may end up with a greater backing in the end against Israel. Iran claims that so many others are in the wrong, and that the nuclear warheads being built in Iran are being assembled through a peaceful process. It must be solely about building energy. Each time they generate the required amount of energy, another dictator joins the party. He's that much closer to mastering the Zumba.