Hi, I have a 15" MBP (early 2011) with the standard 2.0GHz core i7, 4GB 1333MHz DDR RAM and a 500GB 5000rpm HDD. Now I want to do some upgrades, to make it faster, I have noticed that the HDD really is the slowest factor, especially when booting and starting programs. So I want to install a third-party SSD, but I don't want to sacrifice the 500GB of storage. Because I really don't need the optical drive, I'm planning to buy an optibay mount, and mount a OCZ Vertex 2 (120GB) in there. But I've got a couple of questions: Is it a good idea to put the SSD in the optical bay? Or should I switch it with my internal HDD? Will this installation have any influence on battery life? (positive or negative) And is the OCZ Vertex a good SSD and is it compatible with Mac OS X? (I'm running Lion DP4 atm) I've also been thinking about upgrading the RAM, but I'd like to buy only one 4GB SO-DIMM but is it possible to have two different RAMs in one machine? A 2GB from Apple and a 4GB from a third-party manufacturer? Will there be a significant improvement of performance after upgrading my MBP?