I recently purchased a 17'' iMac. I'm considering upgrading the RAM in the next month or so but was wondering about a few things. I purchased AppleCare and was wondering that if I upgrade to 2GB of 3rd Party RAM, will Apple blame whatever problem I have on that. I know I've read in places to keep official Apple RAM handy because that's the first thing to be be blamed. Should I do that, and if so should I just keep 1 512MB stick or both. I would really like to just sell both on ebay or something.