Really late on this response but maybe it'll be useful for someone in the future, I did change my RSM but noise was still present so I got my subframe reinforced by a shop in like late October. Sadly noise was still present after that job as well. What it ended up being was the CSB was toast. Kind of annoying the shop wasn't able to diagnose, they had my car for like a month and half and insisted it wasn't subframe cracking and just thought it was due revshift bushings I had installed. My guess is they never really checked the driveshaft as much of it covered by a heatshield. Final cost was like 2600 bucks for reinforcement + subframe and differential bushings (had them revert back to OEM just in case that was a factor).