Lion upgrade on early 2009 MacBook (2GB RAM, 2.0GHz Intel Core 2 Duo) Is it advisable to upgrade an early 2009 MacBook (2GB RAM, 2.0GHz Intel Core 2 Duo) from 10.5.8 to Lion?  Under 10.5.8, the user is complaining about some 'slowing down' (especially after a few days w/o restarting).  If we upgrade, how strongly is it recommended to increase the RAM (to 4GB? to 6GB?).

I'd love to hear from people answering based on either the specs or first-hand experience.  Thanks.
I have a late 2008 MacBook Pro 5,1 2GbRam 2.4GHz When I updated to Lion, I had no major problems. I had always planned to upgrade my Ram so after one month I did 8GB When Apple said my MBP can only take 4GB. 8Gb of RAM cost $40 on Amazon, best investment I made this year.