An OCZ vertex 4 128 gigabyte ssd can be bought in the UK for £90 yet Apple charges £200 for their msata ssd upgrade. Would you be able to just buy the base model and install any aftermarket msata ssd size that you want? Although it my be an custom Apple msata which is slightly longer than standard and may be hard to acquire. I don't want to pay such a premium for a small 128 gigabyte ssd. In time 128 gigs is going to be pathetic.