Quoted from SilverballNut:

So, mods are a personal choice so have fun with those (I have quite a few). As for the must have fixes, this is what I did to mine and it's a blast to play. Still a hard game as it was meant to be, but doesn't seem like it is cheating you.
- Install Code 1.11 (there are bugs, but the mode progression is well worth it)
- Use a punch and a hammer and bang up the outside rails about 1/4" I don't have any problems with lane hops
- I chose to install cliffy protectors to help prevent any possible playfield damage
- I bought Art's airball protector and installed it. I still get some, but this helps tremendously.
- I put a stiffer spring in the autofire coil so it would not fire as hard (may go stiffer yet)
- I decreased the power of the trough eject (in settings)
- I moved the adjustable posts to be in the tighter position (right side is a pain to do, but worth it)
- Check your slingshots and make sure the big rubber ring is below the small rubbers on the posts. This puts the big rubber ring in the middle of the ball path and the slingshots are more active.
- Level the game at about 6.5 degrees and make sure it level left to right
- Installed the tilt bob (and adjust ring), but it's pretty loose
Then play and enjoy the game. Keep in mind it will kick your butt, but when you get a good game going it is so gratifying. If you really don't like the way it plays, then you can look into the center post, outside lane guards, etc...

Quoted from Chisox:

It's in the service menu but I believe only with 1.1 or 1.11 code installed.