I just checked Apple's website and discovered that adding a SSD adds a different price to every laptop . For the 13" 2.3 GHz a 128GB SSD it is $250, for the 13" 2.7 GHz a 128GB SSD it is $200, for the 15" 2.0 GHz it's $200 and for the 15" 2.2 GHz it's $100. Does anybody know why the same 128GB SSD costs differently on every MBP?