Originally Posted by yuhaoyang
I was agressive enough to severly damage one bushing (x shaped mark left on it)
I have no idea why you would even follow the advice to use the head of a screwdriver as a viable tapping device. You should have foreseen SOME type of damage happening, when you tap the relatively sharp edges of a hardened steel screwdriver head in to softer metal bushings. There are tons of better implements to use.
I wouldn't be surprised if you caused some smaller scale damage to the other bushings. Even small indents on them from the driver head could be enough to score the axles of your gears or the side that contacts the face of the bushing.
Lesson learned: consider the sources of "advice" you read on the internet.
Now that you've widened the holes in the gearbox for the Element bushings, you may find that any other bushing you install will end up being a bit loose. Hopefully not too loose, or you'll end up damaging your gears.
Lesson 2 learned: Buy cheap, buy twice.