I have the chance to buy a brand-new MacBook Air, rev C (2.13 GHz/2 GB RAM/128 GB SSD) from an Apple authorised dealer. Originally sealed retail packaging, standard one year Apple warranty. Price: 20% off the Apple online store price. Do you think this is a good deal given the chance that an upgraded version might come out soonish? I could wait a few more weeks but need to buy beginning/mid October the latest. Thanks for any advice!