Let me preface this by saying this was my experience and hopefully is not yours, but it might be smart to check. I had Alpha install a stage II turbo kit. With all the talk about issues with boost turbo failures, that some think has been caused by the lifting of heads causing the head gasket to fail leading to piston failure I decided to have Henry install ARP head studs. This procedure can be done by removing the valve cover. The head studs are accessed without the need to remove the CAMS. Henry was surprised to find that the two middle head studs on my stock 2015 Sling were loose! They shouldn't have been loose. I have never had the cover off since purchase nor has a dealer. It came from the factory that way. I was SO GLAD I had them do the head studs. If I hadn't I could have easily seen an engine failure from two weak points.
Now I am not saying yours could be the case. Just alerting to the fact and hopefully mine is an anomolly. However, it might be worth a check to pull your cover, and get and check your torqued head bolt studs. Because if yours are loose it could lead to failure. Henry is going to be checking their other Sling to test. Hope his are snug and at the correct torque. These engines are assembled in Mexico on a mass scale. I have no idea of their quality control, and would imagine with GM there would be some sort of a machine doing this. I am going to be checking my ARP studs as well in a few weeks of driving to make sure it isn't that casting that the studs are screwed into.
Your Sling is most likely just fine, but I felt it was my duty to put it out there to save someone else of a possible future issue