Thermometer modification
As is well-known, the Q200 does not come with a thermometer from the factory. I wasn't willing to accept that because I missed being able to quickly check the temperature without always having to wire everything up. Since my Q is not the latest model, I had no hesitation in picking up a drill.
You can find various lid thermometers in an auction house or trusted online shop. I wanted to stay true to the original look and therefore chose a replacement thermometer from Weber. The set included the rosette. I believe it must have been a set for the One Touch Premium or Mastertouch. In any case, I liked the appearance, so I decided on it.

First, the lid had to come off, which is quite simple on the Q200 by pulling out the pins and removing the mounting bolts at the back.

The size of the thermometer determined the position on its own. It was important to me to go as high as possible with the position so that the thermometer wouldn't interfere when opening and closing the lid.

I marked the hole with a felt-tip pen and also the position of the retaining tab of the rosette, which I did not use later. I carefully bent the metal tab on the rosette, which is supposed to help prevent twisting, inward. The thermometer holds on the paint of the Q without an extra notch. Then I drilled; the result is shown in the image.

I determined the drill bit using a caliper; I didn't even need to add anything because the thread went through directly after drilling. The thermometer is secured from the inside with a wing nut. That was really no challenge.

This is what the result looks like. For a rough indication of the temperature, the thermometer is sufficient. You can, for example, easily read when the grill is hot enough to add food during preheating.
Real deviations occur especially when cooking passively because then the warm air is directed very directly at the thermometer. With the lid tilted, it doesn't work in the other direction and shows too little. It's a rough indication, and that's all I wanted; everything that requires more precision, I wire additionally with core and oven temperature probes. The modification has definitely paid off for me.