I am getting the iBook in the mail today. I will be getting the RAM next week. Should I install Tiger over Jaguar today or should I wait till I get the RAM. I have heard a million mixed reviews on how well Tiger works on 256 (and 640!!!). Another side question is, If Tiger is too slow for me on 640mb- how easy would it be to downgrade to Panther? Same process (hold down C at startup)? Thanks!