Hotchkis rear leafs or rms 4 link? Any thoughts?

Yea, you mainly gotta give what your plans are. If you plan to just cruise and no true racing of drag/autocross, then IMO no since spending the money and extra modification for the 4-link unless you just want the extra ability and nice feeling.

But, of course for me, I don't plan to do any of that professionally and I am going with full RMS, so I can't speak much.

Now with that said, both are very good, I have seen both on the track and both performed very well when compared with other systems. (Saw a 69 charger with a 6.1 swap and keisler 5spd w/ hotchkis full system walking away from a 2010 charger srt8)

So, all up to what you wanna do, spend, and have.