Hi, i am from brazil and will travel to USA.. Will buy 5K retina imac, but want buy custom imac (512gb ssd, i9 and better gps), probability won't have this option in stock on Apple store.. It's possible pay using cash (can't be debit or credit card) in apple store and then wait to pickup custom config on same or another apple store few days later? For me buy using money is much cheaper than using credit card because brazil tax about 7,6% when use international credit card, and also exchange rate is about 3% bigger on credit cards, what means if I buy using cash it's about 10% cheaper (or less expensive)..