Well, you can get the drive from wherever your friend got his/hers. You can check Pricewatch.com for the best prices on these things.
In terms of openining up your S to do the upgrade you should know that it “voids” your warranty should any problems occur.
The process of opening your Type S is tricky and involves a lot of steps so you’ll want to be very careful during the process to know where everything goes. Read the following below to have visual step by step.
http://notebookforums.com/showthread.php?p=338323#post338323