Since you are considering upgrading the drive OWC sells drive upgrade "kits" that contain the new drive plus an external Firewire and/or USB enclosure to put the old drive from your MacBook in.
  1. You remove the old drive from the MacBook
  2. install it in the external enclosure
  3. install the new larger drive in your MacBook
  4. Boot from the old drive in the externall enclosure then either…
    1. Use Carbon Copy Cloner or Super Duper to clone your system from the external drive to the internal drive or
    2. Install a clean copy of your OS on the new internal drive and use Migration Assistant to migrate your data and applications from the old drive in the external enclosure to the new drive.
  5. When you are sure everything is working correctly, erase the external drive and use it as a backup or even an emergency boot drive for your system.
As to the OWC memory I have used and I am currently using it in all my Macs with absolutely no problems. I have enjoyed similar results with OWC external enclosures and right now have two that I use all the time.

If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein