Hey guys, just configuring my brand spankin' new MBA. I have two part question. I want to spend an extra $100 on configuration but I'm torn as to where to put the money. Is there much of a performance difference between the 1.8Ghz Intel Dual-Core Core i5 processor and the 2.0Ghz Intel Dual-Core Core i7 processor? Would it be worth putting my money there? Or, Should I just bump the memory up from 4gb to 8gb? What will provide the biggest performance enhancement? Thank you!