Can it fit?

Yes.

However, note that the inlet is 2.25. I think the srt6 needs 3 in inlet (someone correct me if I'm wrong).
I ran 2.25 in duals, so a single 2.25 inlet is not a good idea. A exhaust shop can always make it work though.

I know you have been looking for an exhaust setup for a long time now. Continue to take your time, getting the right exhaust note that you like is not easy. One of my personal favorites, excluding my own, is the ansa muffler that can't be had anymore. Worth every penny, but almost 3 times the cost of this muffler.