Quoted from Zitt:

He asked about "blue ball guides" ... ie the inlane guides which are factory from stern.
I'm assuming Not the slingshot plastics you are talking about.
I'm not aware of any alternate vendors for those ... yet.

Quoted from DaveH:

So this just comes down to a lot of play in the system. Most of the time this is just someone being careless when they took the ball guides out last time. So the first thing to do is to take the ball guides out. Make sure the bottom plastic post parts were fitting right and not pinched. Then usually it’s just a matter of putting them back in, and adjusting them correctly so it lines up. Tighten just enough to hold them and roll a ball down the i lane. Any hop or looseness, readjust. Tighten a bit more, and keep checking to make sure they are right. Finally tighten and check. It should only take a few minutes to get it right, and will play much better.

Quoted from D-Gottlieb:

Excuse me, are those aluminum flippers?