Well, I couldn't take it anymore. The tab that breaks is the upper one around the middle. After placing the part back on I don't notice any fit and finish issues as the other three fastening mechanisms do just fine.

If I get time, I will try to post some pictures on this thread and another that I found here.

 

It should not be anything too serious. Usually if it is from the seat, it's just from the seat. Nothing to do with the engine... Hopefully.

But you do have to send to workshop, just in case. At worst, it might be just the wheels...

 

I finally found a way to take the side plastic panel off the seat without breaking that one clip!

Unfortunately I broke the clip before finding the solution.

The cover that the clip is attached to has a screw on the lower seat side. Remove that screw and you can take both covers off together without having to break the clip.