Can some people that have done this upgrade (stock 5400rpm to SSD) comment on how difficult it was and how long it took them? I've looked at the ifixit guide and it seems a little daunting. That being said, this 5400rpm drive is driving (hah) me nuts. Is it hard to get everything back in afterwards? I feel like reassembling would be harder than taking it apart. Also, how would a SSD compare to a 7200rpm drive in both speed and lifespan? Thanks!