Thanks to Invid, my AS is no longer starting on its own!
I think I can help you with these two. Disabling Error reporting did not seem to have an effect on my processor speed, but disabling automatic syncing (and activesync startup) did. The new activesync is a dog, even worse than it was on WM2003SE and makes my x50v almost useless while running. I will list the steps to disable it. Note that you will still be able to sync, but AS will no longer start up on it's own.
1) Start up AS on your x50.
2) Tap the menu tab/soft key and tap "Add Server Source"
3) Configure a server source with a dummy IP address, user id, password and domain name; these do not have to be real
4) Once configured you should have another sync source show up on your main AS screen...continue on.
5) Tap the menu soft key again and you should see that the sync schedule option is no longer greyed out.
6) Change your schedule from a timed automatic start of AS to manual under both fields
7) If you try to sync now, AS will try to contact your imaginary exchange server and that will take forever until it times out, so you can now delete the exchange server from your list of sync sources. Your changes to the sync schedule will remain and will survive soft resets too.
If you have a switcher app running (like vbar) you will find that when you close AS it will now stay closed and you should see a corresponding increase in speed.
Post some feedback and let others know if this worked for you. I am not really sure if this is what sped up my x50v but I know that it no longer slows down to a craw on a regular 5 minute schedule and AS only starts when in the cradle or when I start it for BT syncing.