Salaam brother,
Actually there aren't many differences between the Shi'a and Sunni school of thought...
The only differences that are there are in Jurisprudence.. and even then they are minute...
Even within Sunni School of thought you have people with different Jurisprudence.. There are 4 Sunni madhabs (Hanafi, Sha'fi, Maliki, Hanbali). The Dean of Al-Azhar University (Biggest Islamic University) Said that: "The 5th Madhab in Islam is Ja'fri(Shia)"
Having difference of opinion in Jurisprudence isn't that big of a deal... It doesn't mean if a person prays differently that he is not muslims anymore...
Most of the Ahle-Sunnat pray with their hands folded... But the Sunni Maliki's Pray with their hands on their sides, just like the Shia..
So it's not such a big deal... every school of thought, madhab, has their own proves and hadith to prove what they do is correct... we cannot say one is right and the other is wrong.