I would not try swapping the SSD on an ultra-thin laptop.
That's coming from me, as I type this on a laptop I built from spare parts gathered off FleaBay.
The thinnest laptops use mSATA drives or 2.5" drives that are significantly thinner than the traditional 9.5mm. If You get a 5.5mm SSD, it will be difficult and expensive to find a replacement.