You won’t need chains if your traveling on regular roads. If you do decide to buy a set make sure you know how to use them properly. Teton pass does close if the conditions get bad. I’ve used a tow strap and shovel more times than chains.
I had my muffler removed also, it is loud and a lot drone. I have been driving around in L9 because it is terrible when it starts dropping cylinders. I think the flapper is what makes it sound like a helicopter
I went to a local muffler shop and had them cut my muffler out on my 2020 6.2 and weld in a straight pipe for 80$. He did mention the pipe sizes were different from previous years he’s done. He welded in a 3inch pipe