I have some questions about buying an imac from amazon.com. mainly with the apple store, you can choose the specs you want your computer to be(within reasonable limits) but it seems with amazon.com you can ony choose from the basic iMac 17" basic iMac 20" and so on and so forth. is this true? is there any other reseller that i can buy from that will give me the spec choice i want? if so please tell me about it. i really dont want to pay the $150+ i will have to pay in sales tax.