I'm going to buy a Nexus S off eBay and some end in a few hours so please reply quickly! . I want to know which model works with 3G in all the Americas, is Super AMOLED and is GSM, please give as much detail as possible. There are many different models and I'm new to this so I got confused and on top of that eBay can sometimes get crazy . Also, is there a difference between a GT-i9020 and a i9020a model? Thank you.