It depends where the squeak comes from. There are lubricants designed for plastic and adding such in a correct place certainly may help. Any grease will help for a while, but if you don't want your stick to crack into smithereens because of the lubricant making the plastic brittle, get the real stuff. A local lubricant specialist shop might give some hints, an automotive shop may sell the stuff cheaper. Hmmm... a fishing reel lubricant might be a good choice, they sell it in miniature tubes and it shouldn't harm the plastic gearwheels it is aimed for.
In X52 there's also this big string, having a metal to plastic touch. You might try the X52 stiffening mod shown on
this youtube video. Not only does it improve centering, it also adds a totally new surface for the spring to scratch. The above mentioned lubricant might do good in between the stick and the ring.
