Ditto on the dimpling, it's normal. Waxing will have no effect on dimpling. Eventually you'll have thousands of dimples more evenly spaced around the PF and they will be less noticeable than a NIB game that is getting it's first dimples. Waxing is always a good idea IMO even for a NIB game.

Regarding the higher grade steel balls, it's a waste of money for a pinball machine. Higher grade means a tighter diameter tolerance and pinball machines are not picky as to ball diameter as long as you use a 1-1/16" dia. ball.

Get yourself some carbon fiber Cliffy protectors for both magnet areas and the mystery scoop cliffy as well.

I don't have much to comment on the chip other than that sucks. Hopefully you don't have any more issues like that pop up.

It also comes in fluorescent green or yellow. I believe the one you have pictured is a fluorescent color underneath that paper since it has the spiderweb design. The clear protector is plain with no etched design.

As an example, it only means the difference between a 1.0625" and a 1.0630" ball. Both of those balls will play the same. The pinball life shiny pinballs are highly regarded amongst pinsiders and I have no idea what grade they are nor do I care.

Here's a rulesheet: http://tiltforums.com/t/metallica-wiki-rulesheet/228

PAPA also has a good video tutorial, just google it

Everything is here including the mystery scoop protector: http://www.passionforpinball.com/Metallica.htm

You will also want to get the 2 carbon fiber protectors for the magnets. I would also recommend getting the 3pc shooter lane eject protector set.

That magnet core looks fine! They get heavily dimpled during normal use, but if it's deflecting balls them it's time to grind it flat again or just replace it.

It's not hard to remove, don't let what you read deter you. Just make sure to remove it through the top of the PF when you need to, so you don't try to screw the top down through the playfield and out the bottom.