The taller 5th gear should be a nice move I'm in favor of it but I've never had one. Will someday.
Just wanted to tell you that a little pitting of the gears is so common it's almost normal. The silvery bits you found were not from any gear teeth. The silvery bits were from bearings and their races. These wear and eventually start falling apart. Gear teeth wear but IMHO not as much until the trans spends too much time with water in it. This is what causes the pits in gear teeth.
The above is my opinion.