I think I may have found the answer to Issue #1--thanks to MaryGladys on this thread:
http://forum.ppcgeeks.com/showthread.php?t=44183
I unchecked the "Sent Items" folder under "Manage Folders". This seems to have sped up things considerably even though it could still be faster. Hopefully it will continue to perform better. I highly recommend you only choose your most essential folders - mine are All Mail, Drafts, Starred and Trash (could probably be even less). I have label folders but don't bother with them, and the general "Inbox" folder is useless to me. HTH.