Greetings!

Having already had a small bout of gravity with mine (survived very well, I would add), I can say that it is the distance and angle of impact that seem to make the difference. If you are running, display, sound and sync, I don't think you have anything to worry about.

If you want to double-check the disks, you could always run an fsck against them. Drop to shell, and try:

# rwm
# swapon /swapfile
# fsck /drive0 (Note: this may take a while...)
# fsck /drive1 (If you get an error, you might want to try fsck /dev/devicename)
# swapoff /swapfile
# rom
# exit
- try another sync

As for the bent bit, could it have been from the unit being opened while upgrading the drives? On the Mark 2a's,
sometimes the metalwork is a bit too tight to slide the top off without a little, um, persuasion with a screwdriver...
To quote The FAQ(tm):

It's a tight fit as the front tabs travel over the corresponding tabs on the main case, and levering them slightly
upwards with a screwdriver is usually necessary. Be careful not to let the screwdriver damage the sled hooks or
anything else inside the case.