Quoted from PoMC:

Yes, 100% correct on the insane airballs. I bought a Twister recently and the game was near unplayable because it seemed like every missed shot on the posts AND shots on the standups resulted in crazy airballs.
BUT, I found a solution and easy fix. I installed 23-900 coils on the flippers and the game plays great. Yes, you will still get an occasional airball, but the game is a blast to play, fast orbits that feel terrific nailing over and over and fun multiballs.
I don't even have a working magnet board in mine and it's STILL so much fun to play. applejuice is currently working on a replacement magnet board. So don't let a non-working magnet board stop you from picking up a Twister.
This game for sale 100% working is a nice deal.