Recommended MacBook Pro 13 (mid 2012) SSD upgrade? I am going to buy the high end MacBook Pro mid 2012. I want to get an SSD, but the BTO options given by Apple are too pricey in my opinion.
Which third party SSD (512 GB) are recommended (for performances and prices)?

Edit: at a local shop they told me that changing the drive of an Apple product invalidates warranty. Do you know if it's true?
Your warranty won't be invalidated although Apple can refuse to work on it until you reinstall the original drive (so put it away on a shelf).  A local shop might be more flexible. Or not.